Hey Beni! I saw your upvote and thought i might as well post the solution i found.
I used SteelSeries Engine 3.0, and connected the Tobii eyetracker.
It is instantly recognized as the SteelSeries Sentry – and they have an option to render gaze point to OBS.
– Looks quite nice too. Hope it helps, all the best.
Sincerely
– Jens Schmidt