semi-recent (july 2022 or later) versions of talon, the software i have been using for the past few years, seems to work phenomenally with the Tobii 5 nowadays. which is great because the previous version of the hardware (4c) has become increasingly difficult to acquire.
I was using a 4c and I got a 5 today to see if i could recommend it to folks. The short answer is yes! It's smaller, lighter, seems to work as good or maybe a bit snappier.
minor caveat: the hardware ships with broken firmware. you need to plug it into a windows (10 or newer) device for a few minutes so that the windows hotplug thingy can download updated firmware and flash it. But then you can go back to using it with linux or macOS or whatever your jam is if you're not a windows person.
by the way if you're skeptical of how good this could possibly be, i literally play runescape entirely with eye tracker, including fast-paced movement, combat, techniques like safespotting enemies, flinching enemies to avoid getting hit. and that's a game which is entirely mouse driven, if you're unaware.
i know of at least one starcraft 2 player that plays hands-free at diamond-level with eye tracker and sound-control


