you do not need anything to be „high availability”, that just adds a ton of complexity for no benefit. Nobody will die or go broke if your homelab is down for a few days.
tailscale is awesome
docker-compose is awesome
irreplaceable data gets one offsite backup, one local backup, and ideally one normally offline backup (in case you get ransomwared)
yubikeys are cool and surprisingly easy to use
don’t offer your services to other people until you are sure you can support it, your backups are squared away, and you are happy with how things are set up.