https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1807250
So, apparently support for an entire bus class has been missing since ubuntu bionic (18.04 LTS) was released in april. Using kernels from other distros or ubuntus old xenial 4.4.0-134 all provide access to sensor data, suggesting the issue is with current (and shipped) kernels. Three weeks into this not much is happening.
This all suggests that pretty much no one has been using ubuntu on touch devices otherwise i wouldn't be the first one to notice this. Now that the devs know this they have no time for it...