Here you go:
1) Just run setup_wireguard_omv.zip script.
2) Ensure Port 51820 (UDP) is forwarded to your OMV Machine. The script tries to do that automatically via upnp.
3) At the end of the script, you will be displayed a QRCode. Scan that in the Wireguard App on your Phone.
4) Connect from your phone
That's all. All configuration files will be in /etc/wireguard
Please resist from changing IP adresses. That is not neccessary. Only the Interface of your network card that you use to connect to the Internet could be changed.
@ryecoaaron This could be a good template for a Plugin.
I was inspired/used part of this https://nbsoftsolutions.com/blog/wireguard-vpn-walkthrough