I've built something similar along these lines. It's an app that uses your camera to track hand movement. As you move your hand through the air your cursor moves as well and to click you need to show a simple hand gesture.

My experience with eye trackers was similar. The clicking thing is partially solvable with eye tracker + foot pedal combination, but the biggest turn off with eye tracker was poor support for wider monitors or multiple monitor setup. Eye trackers also require you to be in a certain distance from it which was affecting my posture.

These were some of the reasons why I've built Cursorly https://cursorly.app/ It's still in the early stage but I'd love to hear some feedback. There is a free trial for a few days, but let me know if you want to extended it, I'd be happy to do so.