Tabb5

That sounds like the PGP Web of Trust, which has been in use for a long time and provides cryptographic signatures and encryption, particularly (but not only) for email.

Guix’s strict open source policy

That should be: Guix’s FSDG free/libre policy

My answer was “Debian stable”; I haven’t used Guix yet; sorry if that was unclear.

But I appreciate Guix’s strict open source policy and it is still possible to get non-free firmware if necessary—see guix-nonfree.

Debian stable, but Alpine and Guix are also worth considering.

This list gets updated every few minutes:

https://github.com/maltfield/awesome-lemmy-instances

The master list is there in the same repository.