I have said several not-so-nice things about Baldurs Gate 3. However, I also want to point out a good thing: It seems to reward roleplaying in some instances - and the combat seems to reward acting cleverly instead of having high levels.

I just came across this 'Ethel' hag and took an immediate dislike to her. Instead of going the 'usual' approach in such games - exhaust all potential dialog options to not loose any hidden quests - I simply left the dialog, waited until she went into a corner, ambushed and killed her. (Btw., if she goes invisible, you can use area effect damage to make her visible again. In addition, you should also ambush and kill the red caps pretending to be sheep in the swamp beforehand, otherwise they will come and help her. I also assume that you need to pass the check to reveal that the 'sunlit wetland' is a swamp, I don't know what happens if you don't).

This had the interesting effect that a path behind her fireplace opened. In there were a lot of captured people who were now free from her choke. You could even talk to one of the masks (I think it was 'regret'), who told me I should come to Baldur's Gate and get a free drink in her inn. Freeing the girl also was very easy afterwards.

From what I have read, the 'standard' way would be to either accept her offer - loosing critical hits and perception - or declining her offer, after which she withdraws into the cave. Since she isn't dead yet, there is a 'gnarled door', a poison area and a much more difficult fight waiting for you.

Altogether, it seems that outright killing her in the beginning seems to be the best choice to solve this quest. Which is a bit perplexing given the 'established' conventions in role playing.

Is there anything you get by taken the harder fight in the cave?

And by the way, if you don't pass the check to reveal the wetlands is a swamp, is the whole scene any different (For example, the spoiled cake being a nice cake etc.?)