The fact that we are even talking about a "5e mod" for BG3 is honestly rather irritating. A "DOS mod" would be a more understandable request, which could unlock everything, let everyone cast spells from scrolls, cast two Fireballs per turn and remove multiclassing restrictions. Oh, wait..
I was still expecting a faithful Core Rules difficulty setting, like in every other D&D CRPG, but of course Larian knows better. We will get Tactician mode where enemies have more fire arrows and more explosive barrels on the battlefield. Actual tactics and being rewarded for good party compositions and resource management, not so much. "Challenge" will come in the form of thunder arrow spam to push you into lava.
It wasn't unreasonable to expect a D&D title to actually play like D&D. Sucks I just don't like the majority of Larian's gameplay ideas and fixations I guess.