Well, you have the Headscale implementation if you want to go full free software.
But, for starters, Tinc is Layer 2 and TS/HS (WireGuard in reality) is Layer 3. TS/HS configuration is centrally managed, you don't have to touch anything on the clients. I think Tailscale hole punching works better, but also it might depend on your situation (DERP servers are nice, but maybe you can just add a Tinc node).
These are HS available features that I think are not available in Tinc:
Split DNS
Node registration Single-Sign-On / Pre authenticated key
Taildrop (File Sharing)
Access control lists
MagicDNS
Routing advertising (including exit nodes)
Ephemeral nodes
Embedded DERP server
But maybe you don't need that, and you rather have Layer 2 and use broadcast messages. So it depends on your needs.
