Wireguard does more than 1-1 connections, every computer can connect to as many other computers as you like, you can have computer a connect to computer c via computer b, and vice versa, and longer chains.

In my experience this is basically a turnkey setup with Tinc though as it handles all the key sharing transparently, and in your example will only use computer b to do the initial handshake and then let computer a talk directly to computer c. This is especially useful when you have large mesh networks across various LANs and WAN.

I haven't used tinyc - but that does sound like an improvement over wireguard.