Larianisms:
- heavy emphasis on ground surface effects and various interactions with such
- high prevalence of special throwable items and arrows that cause elemental effects for both PCs and NPCs
- high prevalence of barrels in the environment which can be broken open to cause special effects
- heavy emphasis on gaining high ground in combat for both PCs and NPCs
- significant emphasis on moving and interacting with objects as a means of problem solving and battle strategy in lieu of using characters' actual abilities
- alteration of a few spells and abilities to conform more to the principles listed above
D&D-ness:
-everything else in the game
Here's the thing though about your Larianisms, that just sounds like a D&D world that's similarly teched like Eberron (lol artificers) or some whacky plane in Planescape.
D&D is filled with shit like that such as flaming arrows, exploding acorns of death, etc.
Barrels? Let me introduce you to kobolds carrying.. barrels (LOL DDO).
Ground surface effects have also always been a thing such as grease, web, illusionary terrain.
For some it's going to be a writing style and animation style, for others it'll be the fact that DOS uses an AP pool and uses cool downs rather than spells per day / ability usage per day etc.
What I am trying to point out is that a lot of the times when people accuse BG3 of being Larianized it doesn't really make sense.