I recieved my S21 Ultra a few days back (after having first tried a Note 20 which had a fawlty camera module so I returned it & exchanged for the ultra)

When using Dex the option to use my phone screen as a touchpad does not exist, I've looked all over the notifications, settings etc and it's just not there, any ideas?

Also on my Note 20 when I was playing with Dex there was a feature to be able to move the mouse onto the phone screen itself, again I cannot find this feature, maybe it doesn't exist on the S21 Ultra.

Bit stumped, appreciate any pointers.