This is a follow up for my Reddit post. Note that this is relevant for the classic X server (not Xwayland, which doesn't have this problem). If you have an NVIDIA GPU on your laptop, This is probably for you: Ubuntu configures the system with the non-Wayland, classic X server when an NVIDIA GPU is used.
The inspiration is from this article from the DELL site. Although the approach is outdated for recent Ubuntu, the basic premise is the same, that is, to eliminate duplicated touchpad / mouse input from X server configuration.