Even if I am connected to ProtonVPN and not engaged in activity, Starlink will artificially cut my speed to 1/3. When I disconnect, the speed will go back up. Maintaining a vpn requires very very little data, so it's not that.
The test is conducted on a secondary device not connected via a VPN, using the starlink speed test.
This has happened 5 times now so it's very consistent. Not sure why they are punishing users (or just me) for using a VPN
Lower your MTU
VPNs add a little bit of overhead to each packet. If the overhead causes your packet to exceed the threshold of what Starlink is capable of, then your packets will fragment and you'll have a bad time.
Lower the MTU and see if your speed returns.
Thanks for the tips