Quoting: Eike

Quoting: LoudTechieIt creates a problem for you, because your distribution doesn't have enough manpower to maintain all packages.

It does. It's Debian.

Quoting: LoudTechieEdit: On the different versions support: yeah probably, Debian, Red Hat and Canonical do that too. Backwards compatibility and usability sometimes require work. This time though each of these versions need only to be maintained once for all distros.

Except for some special cases with two major versions (which both are security fixed) - nope, this doesn't happen. Version 2.17 and version 2.18 of whatever uses the same places for the files, so they cannot coexist.

As a Debian user myself I just happen to directly be in a position to point you to a package that they don't maintain in their repo and I myself use happily with an already existing deb version and is fully dpkg compliant AppimageLauncher.
Also on versions. For every library I encounter in my development work apt offers like 8 different versions. For example gtk library: 2.0, 3 and 4 and the mosquitto library in several different implementations.
Debian also this year published a desperate request for help, because of a lasting 100% manpower shortage for the debian data protection team.
I've also encountered several times that debian warned me about the fact that this version still had unpatched vulnerabilities.

Edit: I'm willing to believe the flathub maintainers to be more lax than the Debian maintainers and thus leave more unpatched packages in their repo, but flathub isn't flatpack. Fedora has its own repo and a few others do too. This is actually the primary feature that differentiates it from Snap.