Yes, the Switch became the biggest indie zone

???

Like hell they are.

The first two MUA games were multiplatform for all the relevant systems at the time. Astral Chain is owned by Platinum just like Bayonetta. Nintendo is only the publisher for all three of those games. In that sense, they're '1st party'. But what makes them anymore so than Bayonetta?

Nintendo owns the rights to MUA3. Nintendo also owns the Astral Chain IP, as well as the copyrights for Bayonetta 2 and 3. In the case of the later, Development of those games are overseen by Nintendo's own EPD division, which nearly all Nintendo-published games go through. Astral Chain's Co-Director is from Nintendo even. 

I mean, every penny counts but at the end of the day the software sales don't lie.

No. Nintendo's first-party has been excellent game after excellent game this generation, there hasn't been a stinker yet. Third-party is very much welcome (DQXI, Civ VI and Octopath are both some of my favourites!) but the console is selling because of Nintendo, the third-parties are just a bonus really. Sales say that too (though the numbers are muuuuuuuuuuuuch healthier than any Nintendo home console since the SNES)

People buy Switch for the hybrid play-modern-games-anywhere concept and the first party games. The mega seller AAA third party games simply aren't made for Switch because they only target the most powerful systems as that is the target game Sony and Mircrosoft have built their audience to buy - hyper realistic graphics action games, and FIFA games. Once in a blue moon a third party will decide to port downgraded several years late versions of current gen AAA games to the Switch at full price, which obviously have a much lower sales roof since most people who wanted that specific game already bought it in the past few years. So nobody is buying a Switch for the once or twice a year downgraded, years late, full price AAA third party game, but when those games do hit Switch they sell well given the context.

Of course, if Switch wasn't full of great indies, A and AA third party content, and the rare downgraded AAA third party game it would not be the huge success that it is. Those games fill out any Switch owners library. Sure they get the must-have first party games, which is why those are mega sellers because those are the games people buy the system for, but then you have lots of great non-AAA third party / indie games to choose from that rack up solid sales (and they don't need multi-million sales to be very successful because they don't have $50 million budgets like PS4/Xbox AAA games).

I would bet if we had accurate global figures you'd have a ton of indies and third party Switch games in the 1-2 million range and a few in the 3-5 million range - so those aren't system sellers, but they are popular games that sell well and fill out a library that would be looking pretty empty people only bought first party games.

I have 21 third party games and 12 first party games (and I counted Bayonetta 2 and Mario+Rabbids as first party though opinions seem to differ on what they are and I don't really think of them as first party, but basically one-third of my games are first party). I mostly bought the system for the first party games but I mostly buy third party games and I have more indies than I do first party games. And while there are a few third party games currently out that I might eventually get there are only two more first party games currently out that I would think about getting once they go on sale. First party (and hybrid design) sells the system, third party is what makes a good library and keeps the system healthy.

what third party support are we talking about? those 15 years old games badly ported and barely running on the system? That's not what i personally can call a support, that's a hard try to make easy profit from the high sales of the system.
We're at a time where even Nintendo is struggling to support its ONE and UNIQUE system, so forget about third party support.
What's making me even anxious is that it's selling hugely even without Nintendo releasing anything on it ( only one big game this year isn't enough ,and only two first party games to support their UNIQUE system that's really worse).
My point is clear, Nintendo had become lazy and edgy about their products that they started ignoring performance since the wii era, and now they are starting to become lazy even in making well manufactured products (cheap priced components for their system like we've been experiencing with joy-cons).
The fact that a system like the switch is selling like hell won't help for the future generations Thus Nintendo won't try to fix things or make them better. They'll go with the argument that even if it was deficient people weren't bothered because they bought it, so they'll keep in with that same strategy. (boy, drifting problems weren't fixed neither for the pro-controllers nor for the switch lite. They didn't try to remedy the problem they kept in selling deficient products because people are buying them).
with that said, now i fear that they'll go lazy about releasing more games, or making the minimum out of them, because the hardware sold well even with two first party games only. And if nintendo choses to go this way, switch will be left with no games, because third parties are already ignoring it due to its hardware limitations, and it's to be expected that they'll totally forget about the system once the XBSX and PS5 release.

So, if I understand correctly, third party support for you is restricted to big budgeted, highly tech taxing games. Things like Hollow Knight, Celeste, Octopath Traveler and NMH Travis Strike Again are not third party. I see...

On a more serious note, the drifting is something that really does suck. Hard. But the concept and overall quality of the Switch is still good enough to make people overlook that. Hell, the RRoD did not prevent that specific XBox from selling.

For me no, Although ig they put in the effort to meet collectors needs, then more would sell

Basically Nintendo is making portable systems now, so the Nintendo library is gonna be stellar A/AA/AAA first party games, A/AA third party games, indie games, and older third party AAA games (and a few downgraded recent third party AAA games). It's a tradeoff gaining portability and the best first party games while giving up the latest AAA third party games. Unless at some point third parties decide to have another team make full featured portable versions of AAA games at the same time as the console game Nintendo will continue to not get major third party AAA support.

And you need third party support to have a successful system, otherwise you are an N64 that has the absolute best games of the gen but a very limited library so got destroyed in sales. Switch has been slow to get non-indie third party support, but let's remember the past several gens: 3rd parties left Nintendo en masse with N64 after Ninty was cocky jerks to 3rd parties for two generations and Sony came along and was much nicer, then GC got back some support, then Wii was all different with motion controls and third parties did't get how to take advantage of that plus they would have to start making an entirely different version of their AAA multi-plat games just for the Wii, Wii U was a massive failure so again third parties left, and now 3rd parties are in the process of coming back to Nintendo after taking a wait and see approach with the Switch after the Wii U's failure.

It's been a rough relationship with third parties for several generations, but now they are starting to come back, but they still have to make totally different versions of the game (or downgraded and sometimes questionable quality ports) to work on a portable compared to the other systems, and they don't seem to want to do that, and they seem to prefer to make games that show off the latest greatest graphics rather than make AAA games on a less powerful system instead. Furthermore, since they have cultivated their audience on the MicroSony twins for a couple decades now and not on Nintendo systems its kind of a self-reinforcing thing that they expect their games to sell much better on the other systems because that is where they've created their audience. The fact that when they release years-late downgraded versions of AAA games, rather than build same-date versions made specifically for the Switch and therefore not downgraded, and so of course these very late inferior versions sell far less, only adds to the self-reinforcing idea that their audience for AAA games isn't on Nintendo.

But third parties are coming back to Nintendo now not because Nintendo did everything right (see substandard and late online system, joycon drift, slow release of VC games, small system disk storage) but because Nintendo made a well marketed system that has great first party games and a normal control scheme.

Rather than needing to get everything right, I think they just need to not make a major design mistake (Wii U) and not offer control schemes so different that other game companies don't know what to make of it (Wii). Nintendo always offers something new and different, so it is up to Nintendo to get that initial success from system design and first party titles so third parties know they have a market to work with. While with MicroSony systems everyone knows the next system is gonna be the same thing with better graphics so third parties are more comfortable knowing the same audience is gonna show up to buy their new round of AAA action and sports games.