My facebook feed is the same way. Its based on browsing history and whatnot. Personally, I've leaned into it for the twin reasons of its stuff I'll never buy and I prefer being reminded that its shameful that I'm still using facebook at all. Apparently I'm addicted to daily blocking a new dozen or so people, pages, groups that I've never friended, followed or joined. That said:

$4 is plenty fair in my world.

I don't think the developer has any control over the ads. Google selects those?

Best you can do is to report those ads to Google, or get rid of them by buying premium / blocking them with pihole or a DNS blocker

ads?