This is great news. We have been using wireguard on OPNSense (mostly as servers, but also as a client in a few places) in production for some time now, without drama (we found one bug with a trivial workaround, see email chain "Table=off behavior (not adding any route *at all*)" to this list).
We can now upgrade to something formally "supported" ;-)
If anybody else tries to use the hardware appliances provided by the founders of OPNSense (Deciso[1]) as a wireguard server or client, we found the performance on the non-x86 CPUs (A10, etc.) was not great (they have all sorts of ipsec type offloads, but not for WG). IIRC we struggled to get more than a few gigabits per second in aggregate. The Intel
E3 models are able to run as close to line rate on 10G as makes no odds for us.