It’s absolutely allowed.

It’s not as good as previous versions but I am running stock android and I have wifi power saving and phone (background) power saving modes available. I just checked and the estimate of time until zero percent battery goes from 22 hours to 28 hours with the node that limits backup processes, and that is with 59% on the battery.

There was a power save mode on my old phone that made everything grey screen and stuff that was way better. I think I enabled it for a camping trip once and used like 20% battery in 3 days.