But even with them both using Wireguard, there are choices involved that affect performance, for instance whether to use the Wireguard kernel model or userspace implementation, how to configure routing, packet filtering, firewalls, etc.
The only real difference here is how the vpn product implements wireguard: userspace or kernel space, and how well tuned that implementation is. It might make sense to compare wireguard implementations, but (afaik) all are using one of several open source ones. Tailscale did some work to improve performance that they blogged about here https://tailscale.com/blog/more-throughput
What they compare in the article are systems that provide some form of ACL, which is why bare Wireguard is not included. That means there are features in the data path that could have significant performance implications versus a simple tunnel. The impact of using ACL features isn't really a focus of the presented benchmarks, but they do mention a separate test of using iptables to bolt on access controls.
What is purpose of mesh on one physical segment?