I hear you, I also find it weird to put ads for a free experience when the original service is also free and ad-free.

I prefer apps that, for example, offer limited usage for free and full features under payment. I know what others are saying about this not being a side project. For example, Ivory for Mastodon (iOS) is a freemium app with a subscription model for you to be able to full use the app, also not a “side project” but their model works (they previously developed Tweetbot until all the mess at Xitter started to happen last year).