Comment 14 for bug 1912880

I may have found a somewhat acceptable workaround.

I have discovered that the above mentioned behaviour also occurs with a successful suspend

So the workaround is:

Boot up -> suspend -> force shutdown(hold power button) while suspended -> reboot

Then the touchpad should be working.
I am still trying to figure out why this is happening.
https://bbs.archlinux.org/viewtopic.php?id=252711
This is a thread with recent activity about something similar.
Maybe it can be of use to someone.