Hi @onsche, thanks for your query. Although not an exhaustive list, here are a few of the alternative projects that might be of used to use although I am ensure exactly how closely they align with your need for key interactors. Please give me a try and let me know how you get on.
Tobii:
https://www.tobiidynavox.com/en-GB/software/free-resources/gaze-point-1/?MarketPopupClicked=true (FREE)
https://www.tobiidynavox.com/en-gb/software/windows-software/windows-control-software/ (PAID)
3rd Party:
https://github.com/EsotericSoftware/clippy/tree/2.25#eye-tracking
https://github.com/trishume/PolyMouse
Also, I assume you have already tried the integrated eye tracking in Windows 10?
Best Wishes,