That's why I don't use flatpaks, either they're not accelerated, or they can't use external libs already installed, or they can't print etc etc. Sure, that's all fixable if the devs were doing a good job on flatpaking, but they don't, as it's quite complex. So we end up with apps that have a reduced featured set. I personally prefer appimages, even if they're a pain to update manually (from official sources always). I have about 10-15 such apps that I update them once a month manually. Everything else is from the official repo.