It took a lot of tinkering, ngl. So far, I've gotten it to run at a pretty consistent 30fps with a bit of slowdown when going into areas for the first time due to shader compilation. Of course, big towns and such shows a bit of a slowdown as well, but nothing game breaking. I'm about a third or more through the main story all played on the Deck. Here's a list of things I've done to get it playable:

• Installed Yuzu via EmuDeck. For whatever reason, I couldn't even launch the game using the standard flatpak version/package version.
• Dynamic 30fps Patch. I tried the 60fps version, but since the game never gets much above 30, I went with the 30fps version since it was noticeably smoother.
• Ran CryoUtilities and let it do its optimizations (increasing vram actually makes the game run worse due to there being less ram. This game/emulator is very memory hungry it seems so skip that one.)
• I use the PowerTools plugin from Decky to set the hardware scheduler to performance mode. I've also played around with increasing minimum CPU clock speeds, but I can't seem to make a difference with those. There were some rumors about disabling the "Odd Number" core option that helped performance, ~~but I didn't notice a difference with the current EA build of Yuzu.~~ that turned out to be true.
• Using the normal Power Options, force the GPU clock speed to max (1600).
• Running EA Yuzu in Vulkan mode I'm not sure if this makes a difference, but I sourced the game from a specific girl who claims to be fit and likes to repackage things.

A quick note : I'm also running Release 1.0 since whenever I try to upgrade to 1.1, I get an infinite black loading screen. I think this has to do with where I got the 1.0 release from, but I'm not sure. Supposedly, 1.1 has some bug fixes and performance fixes as well, but I'm too far into the game to worry about getting it working at this point.

All of this is purely hypothetical, though, obviously.