embee
Lawyer by day. Rules lawyer by night.
It's a Critical Role problem. CR allows the players to drink the healing potion as a bonus action.I agree with everything else, but a round is still only six seconds long, and an action isn't even everything you can do over the course of those six seconds.
Of course, I also rule that a healing potion is like a can of soda rather than a shot, because it's supposed to feel significant.
Six seconds is a long time. You can drink a 16 oz bottle of water in six seconds. And most potions, RAW, "consist of one ounce of liquid." (DMG at 139). Hence the belief that, sure, just pound it back in your bonus action.