The op probably refers to the game published by Electronic Arts named “Fe”

Nintendo
-Fire Emblem: Three Houses
Others
-Stardew Valley
-The Walking Dead: Telltale Series (All Seasons, but start with the first)
-Batman: The Telltale Series Seasons 1 and 2
-Spyro: Reignited Trilogy
-SpongeBob SquarePants: Battle for Bikini Bottom Re-hydrated
-Bug Fables: The Everlasting Sapling
-Dragon Quest Builders 2

Hint: The OP listed a ton of games from third parties that he's played, and didn't ask for just Nintendo recommendations either. I can only assume you chose to be snarky because he commented on how Nintendo had "kind of a poor calendar in 2020", but I think what's being implied is that he/she caught up on their backlog in 2020 because of that, not that they were shitting on Nintendo. No need to be rude or defensive. 

Personally the games I'd recommend you are: 

Touhou Luna Nights:

This is a really good game if you like titles which have simple mechanics that have a lot of complexity and depth. It's also a really great title if you like 2D sidescrollers that focus on both hard boss battles but also challenging rooms that interconnect between each boss. As much of the enjoyment comes from the boss battles as they do navigating hard rooms with a lot of traps and enemies. Just be aware the game is kind of short at about ~4 hours. It has an extra chapter though that you can look up how to do, that adds about ~2 hours, a lot of that being due to it's difficulty!

Axiom Verge:

Doesn't really specialize at the same things as a lot of other Metroidvanias. In particular, combat and boss battles are actually it's greatest weaknesses. But it is also the Metroidvania I've played which feels the most like an extension of the genre, really pushing it forward in a few interesting ways. 

It's like Metroid made by Valve, in a sense. Pretty good story with weapons and gadgets that change the way you interact with the environment in surprising ways.

Castlevania Collection: 

Probably the greatest retro collection on Switch from a value perspective? I guess you could argue the amount of games considered as "amazing classics" is somewhat small (pretty much Castlevania 1, Castlevania 3, Super Castlevania IV, and Castlevania Bloodlines), but the inclusion of nicher releases as well as the Japanese version of most of the games (which is pretty much essential for 3 given how much worse the American difficulty and soundtrack is) is really nice. I got into Castlevania with this collection, I've played I-IV so far, and I and III are really great games. II is a misstep and IV feels a bit like a step down (though much in the same way some people consider SMW a step down from 3, where the opinion is very divisive, so take that opinion with a grain of salt), but most of the games are at least pretty good. Excited to get to Bloodlines. This recommendation would be even easier if it included Rondo considering that's the other game considered amazing in the classic series. 

Tales of Vesperia: Definitive Edition:

Among JRPG aficionados this isn't necessarily the best the genre has to offer. But for someone like me who really cares more about character interactions and memorable moments more than some great story (for the most part at least), this is definitely one of the best I've played, especially because it's an action RPG with a fantastic and interesting combo system. One of the only ARPGs I've played where the action element is actually so good that it can stand up to any action game in terms of complexity, really. Also has one of the most beautiful artstyles I've seen for a game, it looks a bit like Windwaker. 

Ace Attorney Trilogy HD: 

I got into AA with this HD collection and while it's kind of hard to recommend a visual novel as it's up for debate if it's even really a "game", this has some of the best storytelling and characters I've ever seen in a videogame. The music is also fan-fucking-tastic, so much so that if the entire Ace Attorney series featured one composer, I'm pretty sure that by the time I'd get to the end of the franchise they'd be my favorite composer in games history. It's a great trilogy for relaxing to, sometimes you don't know what to play and it's nice to just hang out with some awesome characters and great tunes.

Resident Evil Remake: 

My favorite game of all time, which I just played last month. Although, I actually haven't played the Switch version, but from what I know it's pretty good. Takes a while to get used to the tank controls (though there is an alternate control scheme), but I'd say stick with it and it's one of the best games you'll ever play ... probably.

It's basically a Metroidvania with Zelda puzzles as a horror game. 

I also don't know what to play next, because I have so much backlog. Same problem, different cause lol.

I guess I'm going Dragon Quest 2!

Hmmm what? I merely said what I said because I saw a large portion of the OP's game library comprised of first part AAA games, with only a small selection of third party, supplementary and mostly indie titles. It seemed to me that the OP is ignoring a large portion of the system's current and upcoming library. 

But you had to jump the gun on me, for some reason.

19 of the games on OP's list are third party, compared to 25 Nintendo games...

Yeah, no. You knew exactly what you were doing. 

Fire Emblem and Bug Fables are among my favorites not on your list! Immortal is great, I played it on the PS5 but I hear the Switch runs well. Steamworld games if haven't played them elsewhere, Captain Toad if you didn't play it on the Wii U.

You have quite an impressive collection of switch games!  One I would recommend, Mario x Rabbids.  Terrific RPG, good replay, and it’s “technically” 3rd party, so it sometimes goes on sale for 19.99-29.99, unlike what you’ll find on most first party Mario games.  Good luck with your search!

No, Hellblade is not a horror game but it's got a very heavy atmosphere. It's literally dark, you can hear screams on the horizon sometimes, on occasions it gets claustrophobic or you don't know what to expect when it puts you in open spaces. 

BioShock 1 and 2 aren't horror games either but they're extraordinarily trippy, and share also the dark and claustrophobic features of Hellblade. Infinite in comparison is more relaxed. 

Edit: So I looked up if Hellblade is a horror game and most people agree it is. So, yeah, better ignore me there lol Thinking about it now, going around without knowing what to expect is horror, precisely. It didn't scare me, though, so that's why I involuntarily thought it wasn't.