How we got 3 paying users for our app in our first 10 days

A little over a week ago, my brother and I launched our second app on the Apple App Store: Words - Learn New Vocabulary.

Words helps users to improve their vocabulary (English only, for now). The app is available for free, but there is a premium subscription that removes all ads and gives access to greater customization options.

We are quite happy with our results so far, getting over 300 unique users and 3 paying customers in a little over 10 days. Here's what we did:

1. Reddit:
   Since our app is made in React Native, we made a post about it on the r/reactnative subreddit , and it blew up. We got over 100 upvotes, which helped to drive around 50 app installs on Christmas Eve.

2. Apple Search Ads:
   With ~$70 invested so far, the channel has driven about 20% of our installs at an average CPI of $1.02.

3. Google Ads:
   We only recently started investing on the channel using UACs. So far we got about ~20 installs at around $1.50 CPI.

For now, Words has mainly been a fun side hustle, but it would be nice if we could grow our efforts into a project that at least pays for itself, since this is something that we both enjoy working on very much.

Focusing solely on PUA probably isn't the most effective strategy. I'm curious to hear from you growth-expert IHs your tips: How else would you go about acquiring new users for a brand new app?