Скачать или смотреть Resident Evil 4 HD Project v1.0 「Steam Deck」

Get the Mod for PC here. https://www.re4hd.com/ even better on desktop.
Game is running off of SD card, literally no performance menu tweaks were used.

The how to:
https://www.re4hd.com/ HD project 1.1 FULL INSTALL is what you want if you haven't used any previous versions of this mod. Follow the instructions for this, once it's all installed and works on a windows PC. Copy game folder to the Steam Deck then install the game via steam. Steam will just find the files and call the job done without changing or downloading new files. After that you want to go in the game properties and add this to the launch options.

WINEDLLOVERRIDES="dinput8=n,b" %command%

Map a back button to F1 on the keyboard for config. If this crashes the game all the setting can be edited in the .ini settings file.