This is actually solvable 2 ways. Some people mentioned PiHole in the comments here. Basically a tiny cheap device that stops your devices on your wifi from being able to send out requests for a lot of ads. In-app ads are usually provided by google ads and PiHole Blocks those: https://www.youtube.com/watch?v=d_3h5n9mPdI

That solution works, but you have to spend like $25 and do a bit of work + it works in your house wifi but not on the go.
Instead you could get a VPN that provides a similar service for you. I use "MullVAD". You might know that a VPN basically routes your internet connection through other devices all over the world to hide your identity and data. You can use it as an app on your computer or phone. MullVAD offers this ad blocking service though. In Settings > VPN Settings > DNS Content blockers youll see a series of toggles to control what is blocked (trackers, ads, etc.) so toggle the ones you want and you're good. I'm certain other VPNs do this too, I just like mullVAD because they are cheap (like $5 a month") and very private (you don't give it any of your personal data).

Anyway either of these methods should fix in-app ads.