http://xmr.nowherejezfoltodf4jiyl6r56jnzintap5vyjlia7fkirfsnfizflqd.onion/opsec/anonprotest/index.html
Go in your grapheneOS settings and search for 'VPN' , find and select more options for orbot vpn after opening the orbot app once and giving it permission to start a VPN. Select the option to set orbot as an "Always-on VPN" and turn on "Block all connections not using this VPN".