Pulling this off requires high privileges in the network, so if this is done by intruder you’re probably having a Really Bad Day anyway, but might be good to know if you’re connecting to untrusted networks (public wifi etc). For now, if you need to be sure, either tether to Android - since the Android stack doesn’t implement DHCP option 121 or run VPN in VM that isn’t bridged.
Slightly off topic, but it turns out Android has a different VPN vulnerability:
https://mullvad.net/en/blog/dns-traffic-can-leak-outside-the-vpn-tunnel-on-android
Only if you dont have tunnel dns configured