There is absolutely a standard volume max. Unfortunately loudness isn’t that simple.

You can have something that peaks in decibels that you can barely hear and sounds that are the same decibels as taking, but skins ear-piercingly loud.

Your TV can only set and perceive level, or “decibels” of the input signal. Sometimes they can have smarter tools like compression, but these are rare and when they are there, usually poorly implemented.