I have seen people posting that there batt last 8-9H but when i ask how they do it i rarely get an answer.
That may be because most of us lucky enough to get that kind of battery life... simply do nothing special to achieve it, so there is nothing to answer about "how we do it".
If I use my device for light tasks such a as reading with kindle, browsing with edge or watching YouTube in low brightness I get 6.5-9 hours. Simple enough, but not particularly useful to you.
Very demanding tasks like 3D design software also drain my battery in 3-4 hours, so when I must do that, I always plug it in. That´s not a deal breaker for me, if it was, I would have bought a Surface Book.
Disabling and compromise the functions of this device i will not do. Beco
I don´t either. Unless using it indoors where you can set it to low brightness is a compromise.
I always said the same, and will continue to: I also had a
miserable SP4 experience until I replaced my unit for a new one. It was not software, it was faulty hardware.
My new unit has yet to experience the first relevant problem, even the first crash (well, after AU my CPU was stuck at 1.5 GHz and battery life reduced a bit, but having that problem for 3 weeks wasn´t exactly dramatic for me...).
Maybe what Microsoft really sucks about... is about producing hardware...