I'm eager to get rid of needing DDNS and open ports just for web hooks. And I can "flatten" my stack by cutting out a reverse proxy / weird port forwarding stuff.
Just the other day I stumbled on DERP [1] their wireguard-over-tcp (over their node network) implementation which they fall back to if NAT traversal fails. While sure, this is partly ipv4 problem, it recently helped me connect with friends behind government firewalls, presumably because the packets aren't recognized yet.
But that sort of automated connectivity during nat traversal failure through a global network of edges isn't something you can easily setup yourself (if you care).
[1] github.com/tailscale/tailscale/tree/main/derp
IPv6 is an option, but not the one true answer (yet?). It helps sometimes.
For Tailscale, IPv6 helps about 7% of the time to bust a NAT connection.
We race all the options and see which works & is fastest. It's likely it's more like 16% or more (I don't have that number handy) in practice but 7% is just how often it would've not worked at all and had to go to DERP relays if it weren't for IPv6 being an option.