The "evil" path does this right now and has you betray the Tieflings in order to gain a potential cure / solution to the parasite problem through Minthara and the Absolute. The problem is that this also leads to every single other option becoming completely unviable (Halsin dies or is otherwise out of the picture). Kagha has no solution for you because if you "side with" her, Halsin gets locked out of the grove and helps you anyway.
Really? Because Minthara didn't offer me anything. She just commanded that I attack the Grove without offering anything at all to me to do it.
Having Kahga be yet another "i have a solution" NPC is a cheap and superficial approach. With nothing to achieve because that too unavoidably turns out to be not true.
We already have that with Nattie and Halsin - and Gith patrol. And auntie Ethel. And the godamn Goblins who dont even know they have tadpoles implanted and refuse to believe it.
Having yet another same - false solution promise - is uninspired, unimaginative, cheap and too repetitive. I would like to have some other kind of content then "looking for a healer who cant heal the problem" thanks.
The problem is that the early game is very, very urgent about you finding a healer as soon as possible so any path that doesn't offer at least the possibility of a cure feels unnatural to choose. It should be the top priority of any character, good or evil, unless for some reason they really like the idea of having their soul snuffed out and body transformed into a Mind Flayer. Any choice that doesn't lead toward a cure of some sort seems forced because of that. Your character would only ever consider it if they somehow already knew they weren't going to transform in a matter of days.
Even if not a cure though, Kagha still needs to offer something to entice you to help her. Maybe she does some druid magic that is supposed to slow your transformation. Or maybe she just points you in the direction of a different solution. Maybe she knows about Ethel and directs you to the swamp area for help.
But if you really insist on her not being able to help with the tadpole at all she needs to at least offer something. Something enticing too if she expects you to put your life or death, immediately urgent quest on hold to do it.