Multiple VPN client connections - One VPN for each LAN device

How can I setup multiple OpenVPN client connections and assign/force each VPN to one device on LAN? So that the local device don't use the normal WAN anymore and only goes trough it's dedicated VPN

This is what I want to achieve:

Each LAN device should have it's own VPN assigned.

If a device is not connected to a VPN it should not have an internet connection.

I already tried MWAN, PBR but I am completely new to OpenWRT and I am struggling to make it work the whole day.