Use the touch screen to operate the phone/camera?

Can I use touch monitor to manipulate my smartphone?

For smartphones that support USB Type-C DP alt mode, you can connect to the models with USB Type-C support, such as M505/T1, for display and touch operation. However, smartphones that output HDMI video signals do not support external touch screen operations.
Please refer to the following artical:

Best External Touch Monitor for Samsung DeX! Tips to Work Smart on Secure Folder

Can I manipulate my camera on Gechic touch monitiors?

No. Camera OS doesn’t support touch signal communication of external touch monitors. You cannot manipulate your camera on Gechic touch monitor.