Proxying a single app through WireGuard while routing everything else through Mullvad VPN on Linux

I'm trying to achieve a specific setup where I want to proxy a single app (lets say, GIMP) through a WireGuard/OpenVPN connection, while routing all other traffic through the Mullvad VPN app. The issue is that the VPN provider doesn't support SOCKS5 or any other proxy protocols(Not Mullvad VPN).

I've attempted to set up a WireGuard connection that only allows GIMP to pass through, but I'm not sure if I'm on the right track and don't know how to do it. Has anyone successfully achieved this setup on Linux? If so, I'd love to hear about your approach.

Specifically, I'm looking for a way to proxy GIMP through WireGuard/OpenVPN while keeping all other traffic routed through the Mullvad VPN app. Any guidance or advice would be greatly appreciated!