Unfortunately Apple has made advertising in free apps unviable with their universally loved by users iOS14.5 update. "Stick it to the man!!!" Unfortunately, this means advertisers who funded free apps cannot pay for apps any longer. End users must start paying for apps now.

I have converted my apps to subscription now away from advertising. I am making a more steady income. I will convert my last app in the next month or two.

Apple sell more devices with this privacy change, and they get big profit in taking a 30% cut of subscriptions. They took 0% cut of advertising.

So many end users choose to abuse app developers who funded apps through advertising. Instead this is a self inflicted wound, end users support Apple making this privacy change, so now end users have to pay for apps instead of advertisers.