On two occasions I have experienced that my Dell Latitude laptops has twitchy touchpads. This has happened on both Ubuntu 18.04 and elementaryOS 0.4 some years ago.
The fix, so far, has simply been to reinstall the xserver driver plus some additional software:
sudo apt remove xserver-xorg-input-libinput
sudo apt install xserver-xorg-input-all xserver-xorg-input-evdev xserver-xorg-input-synaptics
Then reboot computer.