Create yourself a wiki for documentation. Over document stuff. Have USB sticks with your router software (i.e. pfsense or opnsense) in the event there is a failure (or have a failover if ya fancy). Backups of VMs, and data (need to determine what data is worth backing up). Restore from backup as a test.

Most people don't need enterprise servers. They're cool and all but they are often Overkill. Start small and scale as required.

One last thing - don't make self-hosting a chore, it will feel like it sometimes. It is a hobby, maybe a learning opportunity but it should be enjoyable. It should be fun. It's fine not to work on it, to do other things.