Pay attention to the target info rectangle as well, because it will tell you the modifiers on your attack roll, such as half or 3/4 cover. Your cursor will also give you the basic info of whether you have advantage or not(green plus or red minus). Generally speaking I never really needed the line of sight lines because your cursor will give you the info if you hover over a target. If you have LOS it will show up as a sword or a bow depending on ranged or not, or it will show an x next to the weapon cursor if you don't and tell you why.
I recently bought Solasta because of all the posts I read on here. I'm quite happy that I did. The comments are not wrong about it. Solasta is a custom skin on the 5e framework, races, classes, customization are based on the world of Solasta, but the core mechanics are true to 5e. In turn Larian has made a gorgeous 5e skin with BG3 and wrapped it over a crippled DOS framework. The artwork is more polished, the story is right out of the forgotten realms, and the classes, subs, races, customization options etc are right out of 5e, but the whole thing is on a broken gameplay system that makes combat either obscenely difficult or trivial to the point of boredom. I really encourage people to give Solasta a try, despite the fact that it lacks the polish as well as class/race/multi-classing, etc.. I had a much more enjoyable time playing it than I ever did playing BG3. I want BG3 to succeed, I mean I paid for it, but right now if I had to chose based on fun I'd take Solasta.
