Three canceled immediately and one got to the paywall and canceled. You have a sample size of 4 users who engaged. That's not "optimize conversion" territory, that's "call them personally and ask what they expected vs what they saw" territory imo. A 15-minute call with each of them will teach you more than any onboarding A/B test from my experience.
If the three who canceled immediately say the same thing ("I thought this was going to do X and it doesn't") — well that's your answer and copy tweaks won't fix it. If they each say something different — the product isn't legibly positioned yet.
At 130 downloads with 2-9/day organic, you don't have a traffic problem. You have a "does this do something specific enough that people want" problem. Fixable, but only by talking to the people who bounced, not by guessing. You must established a channel of communication with your users.