Seeing reddit reports of gaming throttling more quickly than that, which would make sense since the GPU is going to sit at or near 100% pretty easily with a game and you'll still be seeing a decent CPU load.
The macbook air is probably the worst machine you can think of for gaming. Even without the M1 you won't have a great time. Its the perfect machine for students because it can last all day in a browser and word.
In a lot of day-to-day work that is much more peaks and valleys, you may never see the throttling.