How to gracefully end a free tier?

My first Shopify app I made was completely free. I wanted to learn as much as I could about my audience and learn their pain points.

I believe I have found product-market-fit, and I created a paid plan that includes premium features - only issue is it's not enough value to convert the past users.

On top of that, this app is more "setup and forget", it's very difficult to get them to log back in and upgrade.

For the long term, I'm going to need to trim the free tier value. Do you have any tips for gracefully handling this? Since the first group of users I had have different expectations for the app, should I just call it a loss if I lose them?