I'm trying to add OpenVPN Proton to Android VPN settings

I copied the address, password, and username and used this information to set up the VPN in Android settings. However, my phone doesn’t connect to it. The VPN in the settings is stuck in the connecting/disconnected phase.

Did you add a Protonvpn openvpn profile? You need the proton app or the Openvpn-connect app on your phone.
I dumped all the Proton/openvpn crap from my phone and used Wireguard. So much easier; just install official Wireguard app, open and click add tunnel, then add wireguard configuration you create on Proton website.

Yes, and I need to use the local VPN settings, which is why I asked.

Have you consulted our support article on how to set up an OpenVPN manual connection on your device: https://protonvpn.com/support/android-vpn-setup ?

Indeed, your article still pertains to the utilization of the OpenVPN client.

Thanks for clarifying. It’s not possible to set up a connection for this protocol in the local VPN settings.