What I haven't seen yet is a good self hosted identity manager, SSO sort of thing. I believe bluesky is working on one but I dont know if it will be self hostable (Freudian autocorrect: self hostage)
Another thing I haven't figured out yet with my homelab/private cloud is how to be my own CA and manage access to my machine without teaching my counterparties ssh. I want something like NordVPN offers in their meshnet: anyone logged into the family plan can see each other's machines as if they were local network. Can wireguard accomplish this? I think this is what yggdrasil is too but haven't dug into it.