D&D General Gameholecon Wardens OP allows PCs from variant 5e D&D systems

[TwoSix]

Most rules are either individual player-facing or gm-facing rules. I DM more than I play, so I'm not as knowledgable as most of my player on the player-facing rules anyway. I trust the players to manage that themselves unless I they are new or it sounds really off.

Exactly. It's not the GM's jobs to know what a PC can do; that's the job of the player.

I would say it's best practice as a player to loop in your GM about abilities you have that are outside the norm or might require some GM adjudication when used. Don't introduce a weird ability to the GM in the middle of a tense combat.