I recently bought a new router and went through the Open VPN setup, then settled it in for clients that might be away from my LAN and need to connect. Flag me if I can be of any help.
I'll underscore what was said above, that once Open VPN is running on your router, no devices that are on your LAN need to have an OpenVPN client running. Only devices outside your LAN should have this set up. For example, my cell phone has the Open VPN client and when I want to connect to the cameras when I am away from home, I turn on the OpenVPN client. Suddenly my phone thinks it's on my home LAN and can access my BI server. Similarly I have a laptop that I routinely use away from home (well, not so much during Covid) and it is configured with OpenVPN so that if I'm "sitting in a coffee shop on public wifi" (yeah, right) I could connect in and effectively be on my LAN.