I have it in nix and use the postrgesql backup config + borg in nixos to move the database and files on another host for backups. I would say it is not too complicated as long as you dont want to have it fully declarative (i sill manage users and apps in nextcloud itself).

I use the following a lot:

• Nextcloud for files, calendar and contacts
• synapse + a few brudges for IM
• mail server
• tandoor for recipes and grocery shopping lists
• gitea
• wireguard
• miniflux
• rmfakecloud And from time to time:
• jellyfin
• wallabag

Tandoor is imho somewhat overlooked and really nice.