BG 3 "likely" will have a DM mode as well that you can host D&D games. I say likely only because 1. we don't know for sure and 2. they have already built a DM mode in DOS and to expand and improve in a D&D 5E setting would be good.
There is a chance some of the things in Solasta we may see in BG3 such as inventory (size and weight, not just weight), and creative things such as pushing/shoving both opponents and objects over cliffs etc.
