Not the person who wrote that but i also avoid anything related to Flatpak. The reason is that it adds a lot of extra friction to anything it touches (despite what its proponents may claim), apps ignore various settings, it wastes disk space with pointless duplication and a bunch of other issues i do not remember right now (it isn't like i write those down - i just sometimes decide to try it for something exactly because i forgot all the issues i faced and somehow someone convinced me things aren't as i remember, then recoil in horror afterwards as it turns out things are as i vaguely remember -- of course the main thing i always remember is the distaste i have for the thing, not the individual microdetails that led to the distaste).

Ultimately if something isn't in my distro's repository, i try to compile it from source and if that isn't available, i just use something else.