I don't think its possible for Larian to make BG3 solo-able without removing parts that make this D&D and not divinity. Unless they have the tech built in to adjust ALL enemy encounters to a single player game...I don't see it happening because a single PC just isn't strong enough, no matter how min-maxed. With a level CAP of 10, you are going to see monsters/enemies up to CR 11-14 most likely in the bosses. For a single PC, a CR 5 monster is technically a medium difficulty. A CR 10 monster, in most cases, is impossible for one PC. And since they have built the entire game and there are no random spawns, I don't see them being able to substitute to account for a single PC.
