I know it is a longshot, but it might be worth looking into what NixOS is about and how it could be used as the base of OMV. I have been using OMV since version 2.x and my overall issue is that whenever I want to be on the latest version I most likely have to start from scratch. It is even a lot more difficult if someone's OMV is 2 versions or more behind. I am using OMV 5.x right now because at the time of my setup (which was about May 15th 2022) OMV 6.x had issues with allowing me to use GPU acceleration in Plex or Jellyfin. I have run similar steps on OMV 6 and on OMV 5, but I was able to get it working only on OMV5 because OMV 6 had a very new version of Debian that did not yet have support for those packages.
I definitely don't want to start a heated debate, but from what I have seen, Nix is the Swiss Army Knife of all distros and what I like the most about it is the fact that it has the best way of handling dependencies. One can have any version of any package (and they have most important packages) with any dependencies running in an isolated environment if needed. It can even run something on a shell based environment. I can even run anything once when needed and can cleanup those temporary installations. It can get nix config files from a git repo and has snapshots of all the previous versions of the OS. As long as the hardware does not break (SSD, USB stick or HDD is functional without any bad sectors), you can never break your installation.
On the other hand, NixOS has a steep learning curve and can be intimidating because one can get lost in all the configs and NixOS is a little different than all the other OS-es. The good thing is that once a config is done, you kind of forget about it. Only after a colleague has shown it to me in action I was able to see how good it can be and how well it can work. My first initial impression was that we don't need another OS that appears to complicate things by trying to be good at everything. Please, please give it a fair chance.