The parts I've played so far feel very forgotten realms.
Shadowheart is a cleric of an evil deity. This is very forgotten realms to just have a character casually be evil like that.
You are in a world filled with tons of old ruins from ancient magical civilizations who worshipped now dead gods. This is extremely forgotten realms.
You start the game in an Illithid planes-hopping ship that's in bad shape due to something happening to most of the illithids onboard, then you get chased across several planes by githyanki riding on chromatic dragons. This is very forgotten realms, also very high fantasy- if anything it makes the actual gameplay (as far as I've gone) feel like low fantasy in comparison.
All of the deities and locations mentioned in the game are Forgotten realms. This honestly should be enough to make it feel like forgotten realms, but I can see how the fact that you're kind of in a small map could detract from this. The scope does seem a bit too zoomed in, but remember early access is just the first leg of the game.
Its a very different game from BG1 and 2, Icewind Dale, and Neverwinter Nights. It's combat movement and initiative systems do feel like DoS 2 and there's definitely some things that I think get overlooked in your average D&D game for balance reasons (fire, acid, and other surface effects I'm looking at you). Plus in the tabletop D&D flying, teleporting, and levitating really play a huge part in adding dimension to your battlefields and campaigns and it seems like this doesn't play well with the confines of an isomorphic 3rd person style game. Maybe this is why there's a disconnect from the feeling of forgotten realms that OP mentions?
