I want to play on handheld too. I have two of them: one is an Arm64 Linux, and another is an Android (Retroid). I know people emulate Steam games on Android using GameNative, I still haven't tried. And for Arm64 Linux there is PortMaster. They can run emulating x84_64 binaries, but we get geeked out when we get the native architecture, haha.
But I know that porting things take quite a time troubleshooting, and that time would be better spent doing some post game patches.
Edit: I just tested on GameNative and it works! It is just a bit funny that it starts in a window, but going to the menu and setting to fullscreen makes it play great!