Fun and fairness do not come from the rules, they come from way the adventures are set up where the characters use their skills.
This. So much of this. This statement is Dungeons and Dragons at its very core.
BG3 is Larain's campaign. They are the DM, and we are the players. I'm sure many will disagree with me, but that's the way I see it.
At my table that I DM, I let my PCs drink potions as a bonus action. Guess that makes me a bad DM.
Fun and fairness do come in a large part come from the rules. Saying otherwise shows a lack of experience with TTRPG's. Rules facilitate the framework of the great hobby. Rules facilitate what kind of game it becomes. A Call of Cthulhu game is a completely different experience from a D&D game because of the rules, not the setting (You can have tentacle monsters in both, but the experience of the games vary because of the rulesets).
And yes, it is Larians campaign. But they did advertise that the game used the 5E ruleset. It would be like you inviting players to a game and advertising that you would use no houserules, but when the interested players show up, they get surprised by a whole slew of houserules that vary widely from the game they came to play.
Your example of houseruling potions is a straw man argument.
