If you already have nextcloud, it isn't a bad simplistic recipe manager. I think it needs fom improvement though.

Nice that it natively supports multiple users. Many dont.

If you don't need much storage internally, I like lots of a Celeron based industrial SSF from qotom. For rack mounts, i like used Xeon-D U1-2 servers.

If I need bigger processing power for home, I like Ryzen (preferably 3000 or newer) processors in some of few ryzen entry-level server boards. They can support ECC RAM if needed.

This sounds promising. My kids already have nextcloud accounts in my instance. Not having to fight audiobookself's lack of LDAP auth would be nice.

If you want x86-64 support in fanless, take a look at Celeron (low powered) based industrial PCs. Qotom comes to mind. You can get a passively cooled machine. Most come with a NVMe and 2.5 slot for storage, do doing raid 1 is possible without external storage. I've bern running my J1900 based one for nearly 5 years and haven't had an issue with hardware at all.