Not sure about that. I set up a wg vpn server on a system which then became unresponsive whenever wg was fully saturating the network. Turns out there is apparently no way to throttle or prioritize a wg server, the only way I could think of would be to dedicate a vm to solely the wg vpn and throttle that vm in its networking.
I instead switched to openvpn which can simply be throttled via a line in its configuration.

Besides that missing feature, openvpn also doesn't require figuring out the right iptables commands to verbatim paste into its config as startup and shutdown commands. Setting it up was way easier than wg (though openvpn too wasn't exactly user-friendly).

WG to me seems too clunky and unfinished for more mainstream usage, though I am sure it wouldn't be an issue for a large commercial user like mullvad that will have no issue with all that.