Often a VPN client is tied to Android session. The best way to use it is from when the phone initializes and you have to enter unlock. The VPN of choice and other network settings are selected and the Android connects to the internet. If you want to be certain it is NOT your Android interfering with Open VPN or Wiregaurd, then you will insure that what is set on the Android is inline with what is on the router. Maybe power cycle the router at the same time …give it all a fresh start.