Regarding VPN, you probably have your VPN config wrong. Either you want it to use a DNS server on the remote network (connecting to a LAN at the office for exam

Regarding VPN, you probably have your VPN config wrong. Either you want it to use a DNS server on the remote network (connecting to a LAN at the office for example) or not. Check your VPN config, it should update systemd settings automatically when connecting/disconnecting.