Oh damn, would not have expected that to work. The worst hack I ever used is when I helped a friend install Linux who didn’t have any spare (working) USB drives around. He did have a spare SSD in his PC however, so I ended up flashing the ISO to that.
You could possibly also make a shell script that does this automatically. I believe most flatpak ids follow a pattern such as com.github.user.package, for github projects for example. So you could loop through all installed flatpaks, extract the name, and then add the alias.