

AFAIU bluehost does not support the acme protocol, so you’ll either have to manage your certificate manually or (recommended!) move to a different dns registrar.
If you are wondering which provider you should switch to, basically all the serious ones will work… IDK if this is relevant for nginx, but here’s a list of the supported ones for the client I use https://go-acme.github.io/lego/dns/
If you are unsure and want to experiment before touching your current setup, you could register a new cheap domain (less than 1$, see https://tld-list.com/), use it for your tests, and then not renew it.
If it’s for backup, zfs and btrfs can send incremental diffs quite efficiently (but of course you’ll have to use those on both ends).
Otherwise, both NFS and SMB are certainly viable.
I tried both but TBH I ended up just using SSHFS because I don’t care about becoming and NFS/SMB admin.
NFS and SMB are easy enough to setup, but then when you try to do user-level authentication… they aren’t as easy anymore.
Since I’m already managing SSH keys all over my machines, I feel like SSHFS makes much more sense for me.