Hi!
You can have a look at an older thread where I mentioned several issues, including that although the touchpad works, it does not has the same features between PureOS and upstream: Review of Librem15 v2.
On PureOS, the touchpad has multi-touch (so two fingers scrolling works), but not on other distributions (I am now using the latest Debian). There are quite a bunch of patches floating around, so somebody put a project on github to collect all these patches: https://github.com/kylerankin/psmouse-byd-dkms. And then, a thread on these forums where the developer of the upstream driver jumped in: BYD touchpad multi-touch support?. You can see the mismatch between the features found on PureOS and the upstream…