I am technically below spec (rx 570) and had similar performance in the base game. The only setting that helped was lowering the resolution, and when i did i could actually push around half the settings to medium from min. Outside of the map and icons it wasnt actually much of a downgrade surprisingly, so i would reccomend trying that and see if it applies to you.
It has more legacy dungeon areas for its space compared to the base game, and those areas are also larger. I had a moment that reminded me of ds1 in one of them, but i wouldnt say its like ds1 because of that.