What bike brand is the best?
What's your buying criteria? Engineering refinement, weight, appearance, paint finish, frame material, availability, price?
Any bike that is sufficiently well made to be functional and reliable is potentially a good bike. There aren't really just good brands and bad ones, but there are cheap brands and expensive ones. Even within brands there are good and bad. I have a perfectly reliable Apollo MTB sold by
Halfords that is at least 25 if not 30 years old. It didn't even cost me anything to acquire. I must have done well over a thousand miles on it without doing anything apart from oiling it and replacing one tyre. Yet there are other bikes sold by Apollo that I wouldn't touch with a bargepole, namely the ones with suspension.
Choosing bikes is a question of weeding out the junk, then deciding exactly what your individual requirements are.
Branding is largely irrelevant now with globalised mass production. It only matters if you specifically want a bike built in a certain country and is mostly now confined to vintage steel machinery. Modern bikes are essentially commodities like domestic appliances.