With the screen brightness that high you will overwhelm the differences in compute efficiency and will mostly be testing battery size versus screen size at near maximum brightness. Probably not that useful. The maximum screen brightness of a M2 MacBook Air is higher than an M1 MBA and the maximum screen brightness on the 14” and 16” are brighter again.
post just above yours (apple's 'up to' numbers). outside of that, too many variables; how bright the screen & keyboard backlight is, what app(s) one is using; other running processes. and so on.
Obviously it can matter. My M2 MacBook Air generally gets over 15 hours but on Friday I used it particularly intensively and I was only going to get about 11 hours. Still fine for an 8 hour day. Still no reason to carry a charger for work.
If a M1 Pro MacBook Pro that generally gets 12 hours but in some uses only gets 8 hours, now there is a worry that it won’t last for a full 8 hour workday. So carrying a charger becomes necessary. So now you have to add the weight of the charger to the already significantly heavier MacBook Pro.
My real world use: M2 MBA is the best. One caveat is that my 16" M1 MBP doesn't really get used on battery but the times I have used it on battery it's lasted for quite a while. My M2 MBA is lasting over 10 hours in low power mode and I'm a heavy user. It is the longest lasting of the 3 laptops you mentioned all of which I have owned.