When you initially start your router, the WAN sets up and the system uses that as the default route. When you start wireguard, it changes the default route to the WG tunnel instead of the one provided on the WAN. If you don't specify a 'metric' for routing on the WAN, "change" --> "replace". Meaning that the original route is now gone. The only way to get it back once it is gone is to restart the WAN interface.
But putting a metric in the configuration for the WAN will keep the route in place. Instead of replacing the route with the one from WG, the system will add a new route (via WG) and leave the original one intact (just lower priority, when you set your metrics appropriately).
.. and since you've traveled from OpenVPN to Virtual Machine to get WireGuard up, and seen the contributions all have made along in your journey (I was just a spectator), when you find need to peel off one or more items/IPs/devices to not be on "Dutch" by default.
I will, but for now I want to thank you very very much. I am struggeling with this problem for so long! Now I can finally try to bypass the geolocation!
Before you go... Another tool to test your WireGuard and the mastering of keys, endpoints with a visual interface for popular OS'es can be found by the Developer's site. Thank you Jason A. Donenfeld. All Rights Reserved. "WireGuard"
Two weekend project and you've been exposed to a lot!!!! You managed all conversations and the translation of the data well.
You deserve a trophy too.
Enjoy your journey.