Cannot connect to WireGuard over cell, but can on wifi

The preferred method here is to setup the OpenWrt router as your primary router... then the rest becomes much easier.

But based on the current topology, you have two main choices:

  1. configure a lan behind the OpenWrt router that will be used for outbound VPN connections. This topology makes it such that devices connected to the lan of the Netgear router and devices connected to the OpenWrt router will not easily be able to connect to each other. It's not impossible for them to communicate, but it's not trivial either. But getting an outbound VPN connection like this is trivially easy. The inbound VPN connection is possible, but again, requires a bit of extra work.

  2. Use the router as 'just another lan device' and setup as your inbound VPN endpoint. This configuration would (mostly) preclude the use of an outbound VPN connection (if you want to know more about that, there is a thread here that will cover it, but it's far from ideal).

What direction do you want to go?