Same boat, I like FOSS, using linux for 20+ years yada yada android custom ROM hack stuff what not, but 10 years ago I tested all the reddit app, Sync was far superior so I bought it for like 3$. Now Sync for Lemmy is an impressive experience compared to Jerboa or Connect for instance, so I forked the 20$ for the noads version. Dev looks like a great guy, I have no problem with this.
For how much time I spent using Apollo, I really got a massive bargain for just $5.00. I’m not surprised that people would pay $20 if the app is good and they use Lemmy often.