Please go to Additional Drivers tab, in software & updates, check to see if you have a driver available for your touch screen. Perhaps you can use a USB-C wired mouse to operate your machine, in the meantime.
I would suggest to try it with switching to Xorg. to do that, go to the Login Screen. Click there on Your Profile so that the Passwordfield appears. When it is appeared, You should see a Gear Icon in the bottom right Corner. Click on it and choose the Option ''Zorin Desktop on Xorg and then log in.