As for DaVinci Resolve, installation can be a bit weird if you don’t happen to run one of the officially supported Distros. Because of that, the easiest way to run it is probably via DistroBox, Michael Horn made a great tutorial about that: https://youtu.be/wmRiZQ9IZfc
It wouldn’t be trivial to package such a big app as a flatpak (or snap for that matter) and also maintain it properly, so as long as the original developers don’t do the work I think it is unlikely to happen. But for a tool that I’m going to be using a lot in the future I think it makes sense to invest the time once to install it, even if it’s a bit more complicated.