"Tap to Click" is meant to be configurable in the GUI here:
Settings > Devices > Mouse & Touchpad > Touchpad > Tap to Click
If you don't see that option then the issue is either:
(a) libinput or the kernel have not detected your touchpad as a clickpad correctly; or
(b) You have xserver-xorg-input-synaptics installed so the Touchpad GUI will be missing.
Also note this will be ignored by libinput as it is a setting for xserver-xorg-input-synaptics only:
Section "InputClass"
Identifier "disable touchpad tap to click, enable palm detection"
Driver "synaptics"
Please clarify for us if you have kept xserver-xorg-input-synaptics installed. Because if you have and continue to log into "Ubuntu on Xorg", then libinput has nothing to do with your issues and this bug needs redirecting elsewhere.
"Tap to Click" is meant to be configurable in the GUI here:
Settings > Devices > Mouse & Touchpad > Touchpad > Tap to Click
If you don't see that option then the issue is either:
(a) libinput or the kernel have not detected your touchpad as a clickpad correctly; or xorg-input- synaptics installed so the Touchpad GUI will be missing.
(b) You have xserver-
Also note this will be ignored by libinput as it is a setting for xserver- xorg-input- synaptics only:
Section "InputClass"
Identifier "disable touchpad tap to click, enable palm detection"
Driver "synaptics"
Please clarify for us if you have kept xserver- xorg-input- synaptics installed. Because if you have and continue to log into "Ubuntu on Xorg", then libinput has nothing to do with your issues and this bug needs redirecting elsewhere.