Of course using another distro you want to emulate is much better.

But as it’s debian based, I’m wondering if a better approach would be to use repos from another close enough distro, like derivative distros which decide to build the stuff for the distro as much as possible (that maybe won’t prevent the need of flatpak and the like).

Another approach would be using a package manager that can work on top of any distro, like Guix, at least for FLOSS software.

I use artix, so if something is not in the official artix repos pacman also look on arch repos, then it looks my personal repos (I build some personal packages, but I also use aurutils, so there are packages on one of my personal repos that are really aur packages not mine). As I prefer to package the stuff I can’t find anywhere I haven’t found the need for something like Guix, but it might come handful if in order to include some software which depends on software way old for artix or something similar to that. Just a reminder that Guix and the like will work fine as package mechanism on top of any distro given their approach to keep the software out of the common unix path hierarchy.