Sven is big fan of Ultima7, which I believe were precursors to Immersive Sims.
It’s been discussed before, though my view on BG3 systems and their interactivity is far less flattering than yours.
BG3 is neither immersive (systems are rather inconsistent, and the game relies too much on unpredictable scripting, and systems often don’t make logical sense) nor a sim, really. It does have some nest systems, that the game take neat advantage off every once in a while, and does allow for more player expression than most RPGs.