It wasn't a whole lot of fun trying to connect code designed to operate at L2 (ZeroTier) with the L3 tun adapter they give you in iOS and Android. Fortunately that code doesn't have to be touched too often though :)
Is it open source?
Fortunately WireGuard only encapsulates at L3, if I’m not mistaken :)
I seriously recommend all to try zero-tier. Especially the fine-grained permissions control is fantastic. It is the only one that went so far as fool-proof.