Now, the problem I repeatedly ran into, despite doing every bit of troubleshooting I could dig up, is that it would always get stuck pre-launch on some step involving compiling the PPU modules for the game, meaning I couldn't even get the game to start to see whether it suffers the reported emulation issues or not. Others have claimed to have been able to run other PS3 games just fine on the Deck, and I'd even heard that you "just need to give it time", but letting my Deck sit for over an hour with absolutely no changes to the pre-launch progress kinda made me give up hope on that one. The strange thing, it DOES seem to be opening a separate process/window for the game itself while running in Gaming mode whenever I pull up the Steam menu, but the option did absolutely nothing whenever I tried switching over to it.
So, I guess the most pertinent question here would be, has anyone else here had these shader loading/PPU module compiling issues when running RPCS3 on the Deck?