Can I presume Solasta is to BG3 what Icewind Dale was to BG1+2?
Yes, I would be wary of categorizing Solasta as a Role-playing game, at least to what I personally would expect to get from a role-playing game. Icewind Dale is best comparison I can think of - custom party, linear adveture, very dungeon and combat heavy. It is nicely paced, and I find story, VO and characters are bad-mediocare but in a charming and indearing kind of way. With a bit more budget and development it could become a really neat IP. What they did works, in my opinion (I wouldn't want Solasta2 to become full fledged RPG for example) but pretty much every aspect of it would benefit of a cash injection.