Edit: please don't downvote me for asking for help. I already looked in google and youtube with no luck.

So I'm wanting to play Jak 3 on Steam Deck using PCSX2. Yeah, I know I could just wait for the OpenGOAL port but that's likely 2 or more years away if it doesn't get shut down before then, and I've been wanting to replay the game since like 2016. No I don't have a PS3 and the PS4 version sucks. I'm any case, the main problems I'm having are that the game regularly slows down. I'm under the impression this is due to the emulator constantly trying to fix the whacky shadows in realtime, but when I followed this post, I got new visual bugs in exchange for better performance, which really didn't help. The ground would sometimes be all black, Jak and Daxter's in-game model gets bugged textures, etc. How can I avoid slowdown but also avoid jarring visual bugs? Is it simply not possible yet on Steam Deck? Thank you for any help you can give. Let me know if you need any additional info like screenshots of settings, etc.

Edit: I want to play the PS2 version of the game so I can take advantage of RetroAchievements. I don't want to play the PS3 version. Can the deck even run PS3 emulation well if it struggles with some PS2 and GameCube games?