My private Wireguard network is IPv6 only. SSH on all my remote servers listens on a random statically configured IPv6 address dedicated only for ssh. Since every server has an entire /64 prefix, a random internet scanner is never going to find it (Of course I still secure ssh properly since a man in the middle still sees what IPs I'm connecting to). Some cloud server providers started offering IPv6 only servers at a cheaper price to save money on unnecessary IPv4 addresses, so there's also a financial incentive to move non-public things to IPv6 only.