Cpt_FLAM However, with my new installation in GrapheneOS, I do have connection information, but no “green hand” and no network access.
Which network access, do you mean? To your LAN or to the Internet (routed via VPN)? It is not clear what you try to accomplish.
I use a similar scenario, but instead of pfSense I use OPNsense. Recently switched from the official WireGuard app to WG Tunnel.
But I can assure you with both clients I have/had no issues on recent GrapheneOS versions. So, focus on your config, firewall rules, etc. If works for one device but not for other, not always the problem is in that device itself. See similar discussion here.