I have 2 internet package at the moment, from cable and 4G modem. I tried to combine both with AR300M but it seems that only internet from cable that being used. From what I found, current firmware is using mwan3 package without web UI so I installed luci-app-mwan3. But before digging deep into this complex configuration (for me), I have questions below:
Is it possible to use both connections to gain more speed in total?
If my router joined a VPN using wireguard, which connection is actually connected to the VPN?
With mwan3 outgoing network traffic load-balancing is performed on a per-IP connection basis.
As such load-balancing will help speed multiple separate downloads or traffic generated from a group of source PCs all accessing different sites but it will not speed up a single download from one PC.
In case of a VPN it will pick one of the wan connections and use that. You could probably also configure which wan to use with mwan3.