Reward/earning apps in 2019?

Hi, I have created some profitable Android rewards apps in 2016-2018, but after some policy changes we had to remove apps before Google banned us and I haven't done anything in that niche till now.

We also have seen many poor reward apps, only with few buttons and awful design, which Google banned very fast. Also many good apps were banned too due to policy changes.

I recently have received a letter, that from November 2019 Google does not allow apps made for ads : "We do not allow apps whose primary purpose is to serve ads."

So what do you think about that niche? Is it still profitable business? What about PPI from incentive users in 2019? What about apps such as Swagbucks or CashPirate, which are very popular, will they get banned?

One way, would be to hide app concept, to become survey app or app review app, what do you think?

What exact policy changes in Play Store made you stop in the first place??

Also, the latest November rule does not apply for such apps IF you design the app well. Google's new rules are the same as the ones implemented for MFA (Made for Adsense) websites back in the day. If you design a horrible website which just puts ads all over with very thin content, you will get hit (although from time to time you still find some ranking on first page).
Same with apps - if you design the app to just display ads all over with no functionality at all, you will get banned.

In your case, a reward app doesn't even have ads in the first place. The offers, for which you get paid for, are part of the functionality of the app and you should design the app that way. Its primary purpose is to give users something for free in exchange for their participation in surveys or whatever offered by your sponsors/advertisers. As long as users are happy to fill in the offers to get the rewards, Google couldn't care less.

Made for ads, might be the policy change which got us to think, because most of the offers == ads. I guess if you do not spam, it should be good, right?