If you setup WireGuard in "VPN Tunneled Access" mode to connect a commercial VPN provider, that pretty much takes over your network so you would not also be able to use OpenVPN:
If you setup WireGuard in one of the other modes, such as "Remote access to LAN" as described here:
then it seems like you should be able to start an OpenVPN connection to a commercial VPN provider.
If you are having trouble, look for obvious conflicts like trying to use the same port for both VPNs.