Does an FPS exist that has genuinely good boss fights though?
Doom 1. I don't see why so many FPS games feel like they need to change the gameplay loop for boss fights instead of just giving you an enemy that is harder to beat while also letting you use the same tools and gameplay you used for 99.9999% of the game.
Doom 1 has absolute garbage bosses.
Ep1 - Two barons of hell which are basically normal enemies, they're harmless even with -fastmonsters
Ep2 - Cyberdemon, harmless damage sponge, literally can't hit you unless you're standing still
Ep3 - Spiderdemon, hitscan galore, you're forced to hide behind the central pillar and kite him in circles like a little child