I wanted to hate this aspect of it, but since I like Debian and and use it as my daily driver on a lot of systems anyway, I just couldn't work up enough ire to complain.
Which is part and parcel of distro-maintainer duties - someone has to deal with the complexity, between the upstream project, linux distro or the end user.
Complaining that the upstream project won't support specific configurations or installations reads as incredibly entitled to me, especially for projects like HA or Pihole that aim to be useful to folk who may not know how to fix package dependency issues, fix a broken install, or many other such foot-guns. This would be a magnet for unpaid support.
If one is knowledgeable enough to complain about installing onto an existing install, then one is likely skilled enough to know how to side-load the app and debug and resulting challenges. It's worth noting the upstream provides the installation artifacts!
