How to prevent dock from appearing when using lower hot corners

I'm using an iMac as a second screen for my Macbook Pro through Screen Sharing. In order to prevent the screen saver on the iMac from kicking in, I set the lower Hot Corners to disable the screen saver.

On my old iMac 2009 with High Sierra, I could put screen sharing in full screen, move the mouse pointer to the Hot Corner and it would work as I wanted. Sometimes the dock would appear but with a bit of fiddling with the pointer it would stay down. Now with my newer iMac that's running Catalina, the dock will invariably appear as soon as I move the mouse pointer to the lower corners.

Is there any good way to fix this? I considered it a feature that the dock didn't appear when using the corners in full screen mode.

Obviously I can't use the upper Hot Corners since they result in the toolbar for the Screen Sharing app to appear.

Is it possible to disable the dock completely in full screen mode?

I would like to avoid having to disable the screen saver completely or move the dock to one of the sides.