nope
nope, PiVPN is goring to remove the DietPi configuration, as it is creating it’s own Wiregard server config file wg0.conf. This ia a behaviour of PiVPN.
There is a missunderstanding still
If Wireguard is not installed via PiVPN, PiVPN will not generate or use any Wiregard configuration, as it will use OpenVPN.
I did a test installation on my NanoPi R5S and I got ask by the PiVPN installer to select between Wiregiard and OpenVPN. Means PiVPN is offering both if all conditions (wg kernel module) are met.