In my experience, the only 2 mobile phone companies whose phones drain battery too fast are Apple and Samsung. Apple does this deliberately for older phones, whereas Samsung has this problem even for new phones.
You will not find this quick battery drain problem in Motorola, Nokia, Oppo, Sony, etc. Their phones last several years even with ageing batteries. An 10+ years old Oppo phone I have, still holds almost full charge at idle, throughout the day.
As batteries get older, their capacity to hold charge reduces, but if a phone battery is draining too fast even in idle mode, it is likely due to software, not hardware. And if it is due to software, then the manufacturer company is to blame.