I must say developers of Solasta could at one point do little marketing this is the first time ever that I have heard about Solasta. Because Solasta is Dungeons and Dragons (5th edition whatever) I am interested in it for sure.
I think it is a difficult to judge because they are not fully released yet. I think Solasta could add even more classes even with the ones know I know about example no Druid yet in plans even.
As for this BG3 vs Solasta I am neutral to it and want to play them both and since I have not played Solasta it is difficult for me to compare.