There is a lot of cloth to cut from:
It could be a 3d mario (galaxy 3, odyssey 2) or a brand new 3d Mario.
2d mario.
Mario maker 3.
A new mario kart.
Metroid prime 4.
A new zelda or tears of the kingdom expansion.
A new pokemon game.
An ubisoft game.
Some ps5/xboxsex games.
It can have a very good launch.

But TotK is coming out in exactly 4 months from today and literally we've only ever gotten two videos of it and no other details since that announcement four years ago. Granted, yes, we haven't seen anything about Prime 4, which is slightly less than what we've gotten about TotK, but its also not coming out in 4 months. Take Bayonetta 3 for example, there was zero footage or details about the game for years other than 'we are working on it' until it was announced with a launch date last year.

There may indeed be more problems with the Prime 4 development, but the fact that we haven't heard anything about Prime 4 or seen any footage doesn't say anything one way or another about how development is going and when it is coming out. It could totally come out this Fall and the fact that we haven't heard anything about it yet would be completely normal.

That said, if could be possible Prime 4 could end up being a cross-gen game coming out at launch like Z:TP and Z:BotW, as some are suggesting. That would still give Prime 4 the chance to sell to 140m+ people on the Switch, and allow it to be the big one-player launch game to go alongside MK9. Though if taking this route Prime 4 would likely only get like a resolution boost on the next-gen as they aren't going to redo the graphics for the next-gen version, which makes the likelihood of any cross gen launch game seem much lower. The two cross-gen launch Zelda games we got were the two generations when the Nintendo system barely increased in power (GC -> Wii, WiiU -> Switch) so that launching a game developed for the previous gen didn't look out of place on the next-gen. But that obviously will not be the case with Switch -> Switch 2.

And given that Prime 4 restarted development 4 full years ago, it seems unlikely that they would have switched over to developing it for the next gen rather than for the Switch. More likely than not Prime 4 will just be one of the final big first party offerings on the Switch. 

I'm confused by your comment. The other Prime games came out on GC and Wii. And they still look great today (not sure why you say they are dated). And this is like 15-20 years later...the Switch is wayyyyy more powerful than GC and Wii. I don't understand why you are saying because you think 15-20 year old games feel dated that would have anything to do with a brand new Prime game. Also, same with the full fledged cut scenes thing...what about the Switch makes you think it can't do cut scenes?!

Honestly, the best thing Nintendo could do for Prime 4 is release it on a system that has sold >130m systems when it releases.

Still though yea Prime 4 being a launch title on Switch 2 rather than coming out on the Switch is a possibility sure, I just hope its not the case. And I don't at all understand your reasoning because GC/Wii games have nothing to do with putting Prime 4 on Switch.

I don't disagree with any of your points.  I'm not claiming Prime 4 is in trouble as a fact, just stating my personal fear.  My fear could be wrong.  I hope it is wrong, given the series is excellent.  

Bayo 3, just my opinion, is the weakest in the series.  I liked it, but didn't love it.  Bayo 2 was far better.

Metroid Prime 4.
DMC V SE
A quirky Nintendo-published game on the smaller side much like how Snipperclips/ 1-2 Switch was that will show off Switch's 2 new features.
NBA 2K
A Call of Duty game.

You think it can't be ambitious if it's on Switch?

What exactly makes the cutscenes in Metroid Dread not full fledged? Do they need to be prerendered CGI?

I mean aside from the numerous predictions of MK9 a 3D or 2D Mario game and Metroid Prime 4 as launch or cross-gen title. I'm surprised no one spoke of Monolith Soft which could be scheming any type of projects for the upcoming console, be it a new IP or anything Xeno related stuff.

They'll be instrumental in showing the prowess of the new hardware just like how they did with the Wii,WiiU and the Switch right now.

Also if the next system were to release during Spring 2025, I'd be expecting the next mainline 3D Kirby to be part of the game.

I dont think we'll see MK9 as a launch title. Not with the support of MK8D going all the way to the end of 2023. Theres such a thing as oversaturation. We prob wont get an MK9 until Switch 2s 2nd year. 

I think we'll see Metroid Prime 4 as a cross gen launch title, ARMS 2, some kind of party/collaborative title that showcases the new hardwares functionality and a 3D Mario title

It depends on how far Monolith Soft’s other project(s) are coming along. This year, they’re planning to release more DLC for Xenoblade 3, which includes an expansion story akin to Torna: The Golden Country. Plus they still have staff helping out with Zelda and likely other projects within Nintendo’s other teams.

I’m curious as to what people think of potential third party games for the Switch successor? If it’s as powerful as rumored/leaked, would we see games like FFVIIR, RE4R, Street Fighter VI, or the upcoming Monster Hunter mainline game? Will CoD and Madden finally make a return to Nintendo consoles? What about modern GTA or RDR?

Super Smash Kart (MK style game, but with all Nintendo franchises).
Tears of the Kingdom (not that I think it won't come out for Switch this May, just think they'll also port it if there's no backwards compatibility)
Nintendo Land Style Minigame collection- I think Nintendo Land was a great idea. Not something to build a launch around, but a good supporting concept if done right.
New 3D Mario Game- Hard to believe it has been over five years since Odyssey. Seems like the right time to get a new one, and launch time would be the perfect time.
Smash Ultimater- I don't expect a ground up new Smash game, but I can see a port of ultimate with about 10 new characters+all the DLC repackaged as a launch title, hopefully with some better net code.
Street Fighter VI- With this non-exclusive this time around, I can see Nintendo having this as one of their big third party gets.
Call of Duty- We know it's going to be on Nintendo platforms, so hitting the next system at launch seems like a smart move.
Kirby and the Forgotten Land 2- A little soon, but I think they're going to want to capitalize on the success to turn Kirby into an A-tier franchise for them.

Not an exhaustive list, and I don't necessarily think all of those games will be there. But those are some I think are likely.