It appears another "gigaleak" has gone down, involving Nintendo. According to sources online, it appears that Game Freak has been hacked, resulting in internal data from the company being leaked to the public. Those involved in the hacking community or those within general Pokemon related groups...
So for the rom and emulation side of things the mainline one was YUZU but it got shut down from Nintendo a couple months ago. They were trading and selling that new Zelda game before it came out.
As far as downloading roms, Nintendo is always looking for new sites to shut down that are hosting their IP so good luck. I’m sure there are some piracy reddit and Lemmy resources out there that could help.
As for native PC playing, I doubt in our life times Nintendo will ever release their games on PC.