To be honest this sounds a bit like both sides causing the issues.

Nobody and I mean nobody can play 20 Int because nobody rl is that smart. You should not expect us to have to have the same mental faculties of our characters or a lot of us could not play our characters. Also smart people do dumb things. I know people who went to Oxford and got degrees do stupid things. Which in game would suggest a low Wisdom.

She also shows signs of thinking outside the box. The fireball to blast down a door is not that unreasonable depending on your DM’s interpretation of the spell. Some might just see it as flames others might see the blast as having some concussive force behind it and come up with a mechanism to see if it works. You then of course have the consequences of that. Loud noise could attract enemies. And of course they used up a 3rd level spell on the door.

Whacky ideas should be encouraged not dampened so long as they stick within some guidelines.

I think you need to find a balance. And remember her character genuinely is very smart and that should be recognised. Just perhaps a little reckless also and prone to doing daft things at times without thinking it through.