Of course rpm and deb packages are doable - arguably even faster than appimage/flatpak - but while rpm is usually pretty universal across distros that use it, that much deb can be tricky especially when it comes to “today and back then” differences in libraries, practically main reason why snap, appimage and flatpak were invented, because Ubuntu was a freakfest of dependency conflicts. In other words you may end up with generated package that will work now namely Ubuntu 22.04 but won’t work with 20.04 or future 24.04 just because. Actually I have bumped onto such a problem recently with few things while I was trying out Ubuntu 22.04 to check some things and see how it’s going on their side.
Beside that I have a bit of wall which is hard to break, I’ve made some progress with creating flatpak package but it’s still being… “a butt” about some things and I need to search for help because I’m not so sure if I can tackle it alone. On plus side experience will be SO memorable that future flatpak packages will go easier for me… hopefully… Maybe even to the point I will pack VCMI more often, but for now no promises are made.
EDIT #1 - I guess there is a lesson to be taken from Heroes games, if there is a wall, use catapult. Fingers crossed, maybe it will build itself finally…
EDIT #2 - Another wall, stubborn as… tea break first…