I'm in a similar position with regards to tinc. I'm willing to grant that wireguard is vastly simplified, easier to configure, and likely better performance. But it doesn't appear to currently support routing through intermediate hosts with opportunistic NAT punching, meaning the presented network won't actually be fully connected. Which I might accept and work around if I didn't already have a better option set up...

If you've got a working OpenVPN setup, then it probably makes sense to just stick with that. I'm guessing the real gains are only to be had when you want to overhaul your setup anyway.