So far, I didn't get time to look for another solution, and as far as I'm concerned, we can run it with Debian 10 (with a few easy tweaks), so right now, I set the deadline to June 2024
For now, I didn't see a big "security concern", I still keep a close eye to my server, but it's running smoothly (and I've multiple backups anyways, as anyone should have), I'll continue to support you and the project.
Glad you found some people willing to invest time on it (and that you can trust their work too ! ).