system
A chat on subreddit /r/pcmasterrace
human
Nintendo doesn't release their games on PC, and the only two Nintendo exclusives at least to my knowledge that have been pretty rough performance wise as of recent are Bayonetta 3 and Pokemon Scarlet/Violet
gpt
The fact that Nintendo doesn't release their games on PC means it's a lot less excusable.
Making games for one platform/set of hardware is way easier than trying to optimise for every single tier of hardware and multiple consoles.

In Bowser's Fury the framerate not only cuts in half, but stutters constantly any time you're in a Fury Bowser fight. 

Metroid Dread stutters when loading in new assets.
Pokémon Scarlet/Violet was inexcusably bad, having godawful draw distance but constantly stuttering and only running in 720p in docked mode.

Pokémon Sword and Shield were really bad for performance too, I stopped playing as soon as I got to Motostoke City as I watched some guy load in and out in front of me.

I know the hardware is limited, but the fact that games like Mario Kart 8 Deluxe, BOTW and Mario Odyssey were fine, shows that it isn't the hardware at fault.

TLDR;
Nintendo games have generally been on a downward trend in terms of performance. It's not just Bayonetta and Pokemon Scarlet/Violet