You can try the following to workaround the issues:
Easiest is to just enable Steam Input (this requires Steam Overlay to be enabled also) for both.
More info:
TUNIC Proton 9.0-3
Works with:
Shield Cat Demo Native Linux
Works with:
Having these "input stuck loop" issues in games, is really annoying. Trying to figure out why is also not easy sometimes.
Some more info from Archlinux wiki: ArchLinux Gamepad wiki
Of course, the best thing to do is to try to engage with the developers and let them know about the issue and ask them to try and fix it.
I've tried the above with Steam running inside flatpak on Fedora 40 Workstation (Wayland).
EDIT: Added note about Steam Overlay and Distro info.
Re: Shield Cat, the developer banned me from their Discord server after I voluntarily left.
proton 9.0-3x1 2024-11
Your system information
Please describe your issue in as much detail as possible:
When attempting to play either TUNIC (553420; run through Proton; Unity based) or Shield Cat Chapter 1 demo (1522890; native; Game Maker Studio runtime) with either a DualShock 4 or DualSense controller, if using them in Bluetooth mode, the games are unplayable because the Up direction on some input is stuck. They're playable if the controllers are used wired.
Steps for reproducing this issue: