Nothing about my argument goes against creativity.

It just goes against players who think they can outsmart a DM by rules lawyering. Especially by some "hack" they found online that could "totally do OP damage and is completely RAW".

In fact, it being at the grace of the DM is actually more creative, since you aren't bound by rules.

And to top my argument off, the most important rule in the DMs guide is the first one: Page 4 of the Dungeon Master's Guide:

The D&D rules help you and the other players have a good time, but the rules aren't in charge. You're the DM, and you are in charge of the game.