Gestalt Multiclassing

[XtomJames]

In the D&D supplement I'm writing (and I'm hoping to publish this year, titled Masters of the Dark Dominion) I have a feat that reintroduces Gestalt builds to 5e in a new way. It reads as follows: "If you take this feat, choose one other class, you gain all class abilities form this class as if it were your main class, and you level this class parallel to your main class. You start this class at level one, regardless of what level you have obtained in your main class when taking this feat. You may not take a class of the same type as your main class. (E.g. If you're a Sorcerer you can't take Wizard or Warlock, but you can take Cleric, Druid, Ranger, Bard, or any martial class. If you're a Rogue you can't take Monk, Ranger, or Barbarian, but you can take Paladin, Cleric, Bard, etc). You can take this feat multiple times, each time acquiring a different class."

I think this'd be a great feat addition for the game and help to fix the mutliclassing levelling issue, at least as an alternative. I'd make this as a mod myself, but I have no idea where to begin or how to mod BG3. My modding experience is mostly with Minecraft.