spoilers for baldurs gate 3
so i'm playing baldur's gate 3 right, i'm exploring this cave, and I think "oh, there's a route to that temple of shar over there, i'm gonna jump down and climb a pillar that got knocked down to see what's going on at that temple." only to be greeted to this.

alright, this is fine, there's probably some really cool reveal that they have whenever you get there or something leading up to it. I figure how to work the forge, and I start this boss fight, after 3 party wipes, and I see that none of my attacks are dealing damage to the boss, so I have this idea to use the environment to my advantage and use the lava around the arena to damage it instead. this is what happens when I tried it.

I think outside of the box and i get punished for it? isn't this supposed to be dungeons and dragons, where you can basically do whatever you want to in order to solve a problem and have it work? i mean, my expectations were lowered significantly when i found a ordinary wooden door i couldn't break down (former nethack addict), but come on, this should've came in playtesting.
I gotta come to BG3's defense I'm not sure where you're trying to jump to. At least in my head I see that as "out-of-the-map fluff" meant to be present instead of a boring black void.
Title
Also the boss you're fighting can only take damage while the lava is out I believe. There's definitely moments like that in D&D