I’m not a gamer so I had to look this up. The Google AI answer for cloud gaming stated a stable 15-20Mbps connection as a requirement. Obviously latency matters in many scenarios but raw bandwidth might be overstated?

Geforce Now requires up to 1gbit for the 5k 120Hz. Geforce Now is not yet available on Apple TV, but it's probably a matter of time and/or other similar services will also impose requirements like this sooner or later.