Erick recently published an article about packaging Flutter games (or apps) for Steam on Linux (which makes them playable on Steam Deck, among other things).
It’s a fantastic help for someone like me, and it includes code. I had something similar for GIANT ROBOT GAME before but I still encountered issues on various Linux distros. I clearly need to learn more about containers.
Anyway, now my game seems to work on basically every Linux, so I’m happy. Given how hard it is to make sure that a non-trivial app works on any given Linux installation, I think Steam’s approach (via containers) is solid.
Here’s where I currently ask Linux users for testing help, just in case you want to join the play test:
https://www.reddit.com/r/linux_gaming/comments/1v932ai/i_just_hopefully_fixed_my_upcoming_2d_mech/