Don't know if the packages delete themself after they run. I just wanted to provide some basic commands, as all the other infos I found didn't provide any help.
I'd recommend that you try and ask this in a more specialized forum (e.g. BGG [1]). Also, if solo playable board games is a must - this drastically reduces the amount of games.
AFAIK most cars with electric parking breaks need to be set into a special maintenance mode either via OBD-2 or a special in-car procedure to be able to change the pads. Otherwise the breaks Pistons just push together and leave no room for the new pads. At least that is what my 2015 VW would do. But every shop around here has that Software or knowledge.
So Hyundai just upped the game and put some subscription into their service software. Definitely not a consumer friendly move, as changing pads and even disks is not that hard.
I'm running a 6900XT on Arch and have no problems so far. Steam, Heroic launcher and every game i tried so far worked like a charm. You can even OC with LACT [1] if you want to.
So far, I have tried Qt directly with C++ and python bindings (pySide6, pyQt), where C++ is definitely the lighter option.
If you consider python bindings, you could also look into JavaFX. It has the advantage of native images or the option of a fat jar containing all platform dependant FX modules. But the resulting files won't be small.
I guess you already know, but you do not necessarily need a server for Syncthing if the devices are on at the same time. If they are not, a simple low-power rpi-like device would be more than enough to implement a star topology, with the pi being receive-only.