I didn't really like it, it has a differnt tone than the base game, and it stands out. It plays more like IWD than BG. Also most of dialogues were cringy to me.
It's better in the second half, those big battles are ok.
It would be much better as a standalone game, or a side story to the main protagonist (for example if you could play some guys who were observing what the main protagonist from BG1 did, then went on to some adventure related to that etc), not something that is crammed between BG1 and BG2 and tries to retconn things