Unity doesn’t use a fancy GC, though. Also, that is more than likely just bad game logic on their part — the engine itself doesn’t use GC, most of the objects are not supposed the be on the heap.
I would argue that not using a GC is very task-specific. Besides some audio-system, I really have a hard time thinking of areas where my go-to wouldn’t be a managed language.
low-latency is not free
But again, don't just take my words, ask game developers who use both Unity/Unreal, and ask them why they are forced to work around the GC ;)
Look at the modern AAA released this year, they already struggle CPU wise