XPS 13 9370 Thunderbolt 3 external display not working

Hello, I am trying to use an external display with my XPS running kernel 5.3.0 by using a Thunderbolt 3 to HDMI adapter. The adapter and display both work, and I have tested both with other devices. When I plug the adapter into one of the Thunderbolt 3 ports on my XPS, nothing happens. No thunderbolt devices appear in /sys/bus/thunderbolt/devices, and `boltctl list` does not show any results.

When a thunderbolt 3 device is connected, `lspci` shows the Intel Thunderbolt 3 Bridge as a device:

04:01.0 PCI bridge: Intel Corporation JHL6540 Thunderbolt 3 Bridge (C step) [Alpine Ridge 4C 2016] (rev 02)

However, the thunderbolt device itself is not detected.

Running `boltctl domains` lists one domain (no security) that is powered off. Running `boltctl power` as root gives the message `acquired power guard (7)`. The command continues to run with no output until I quit it. It has no effect on the domains power.

The Thunderbolt 3 to HDMI adapter I am using is not made by Dell, but I know for a fact that it works. I suspect an answer could be to purchase one of Dells expensive docks, but I would much rather fix this issue without purchasing anything, especially since it seems more of an issue with Linux and Thunderbolt 3 power management than with the display or adapter.

I have Thunderbolt enabled in BIOS, with no security (I have tried at every setting), and I have tried every applicable option in BIOS to no effect. My apt packages are up to date and I am running Ubuntu 19.10.