I’m using an app to use my Android phone as a webcam, which works great (good low light performance!) provided I can stand it up somewhere above my laptop screen (finicky). You can accidentally knock it over. Might be worth considering if you don’t use the camera much - otherwise an external one will probably attach better and he more stable
the processor it uses, the Snapdragon 8 Gen 1, is pretty notorious for poor efficiency. I have a phone with it and it heats up a lot (battery reports 45C) from more demanding tasks (such as gps), battery life isn’t the best either.
That said, my battery life has not been as bad as yours… 2:30hrs seems quite poor.