Part of the realism problem is how short a round is in modern D&D. 6 seconds is very little time, vs. 1 minute in AD&D. There are advantages of the longer original round, where it is assumed to be the outcome of an exchange of blows, rather than each side only getting one or two blows.
That video demonstrates quite well that accessing the potion takes far too long, so it needs to be stored in an easily accessible manner. I typically assume that a potion is 1 oz. of liquid. A character that wants to access and drink them quickly would have them in a potion bandolier across their torso. I had a 3E D&D character where I carefully detailed this, with a bandolier of potions, and another bandolier crossing diagonally the other way with throwing daggers.
For those with realism issues for the bonus actions, maybe instead assume it is a magical pill that characters pop in their mouth, having grabbed it with their free object interaction from an easily accessibly container.