@Kim There are many more mods available for that "severly outdated" version 23b of 0 A.D.
So I would not call it severely outdated.
If security of your pc is important to you then of course think about where you are downloading from. Flatpack, snap, etc may introduce the vulnerabilities that you do not want.
You deserve to know these things from the "official" maintainers of 0 A.D.