however, not sure if it's just me. there's no high ground advantage in solasta? i don't seems to get advantage when firing arrows from elevation.
You don't have advantage if you're higher nor in Solasta, nor in BG3, nor in DnD5e.
You usually gain advantage or disadvantage through the use of special abilities, actions, or spells. [...] The DM can also decide that circumstances influence a roll in one direction or the other and grant advantage or impose disadvantage as a result. (PHB 173)
Consider granting advantage when: Circumstances not related to a creature's inherent capabilities provide it with an edge. Some aspect of the environment contributes to the character's chance of success. (DMG 239)
Performed a search and found this. "Some aspect of the environment contributes to the character's chance of success" perhaps i misunderstood this part for getting advantage. However, In BG3, they grant +2 to attack correct me if i'm wrong?
BG3 started with Advantage being given for high ground & Disadvantage if low ground, but changed it to +2 Att for higher and I think -2 Att lower(not 100% on the -2 Att for low ground). The +/- 2 Att BG3 applies has been said to be a reasonable compromise for kinda factoring the optional GM rules on cover into the game. Personally I think Larian should remove even the +/- Att along with the overblown trajectories bows have and make them straighter like spells. Higher ground in Larian's game is advantageous enough without adding mechanical bonuses and negatives.
Edit: that was OT, so on topic +1 here too for optional full control. I'd play it, not trying to force it on all.