Better late than never. The last few days have been full of virtual machines, linking and compiling. Apparently you can't simply move a file onto another PC and expect it to run. After some tweaking I finally managed to put together a system for creating a single "AppImage" for my games making them a bit easier to distribute, at least on GNU/Linux.
Here's a hello world in a virtual machine with zero dependencies installed

Maybe I'll also have web builds next time around but that will require a bit more work. Windows builds I had to skip entirely. That just didn't work and that dreaded g++.exe still gives me nightmares.
On another note, I also had some success with a raspberry pi (ARM CPU) and also in theory this all should run on a Steam Deck but that one I can't test because I don't own one.