So without Dubbel and only the trusted certificate, AdClear is able to block ads on Android 6. No matter what you have browsed or watched, everytime you open the app, it just shows that same set of videos on the homepage and does not show any suggested videos based on the videos watched earlier.

NewPipe only shows a 'Trending' page depending on the country that is selected in the settings. I don't think NewPipe or any other app (except Vanced for which I need to disable MIUI Optimization that would clear all the permissions from all apps) is able to do that. The main reason for using the YT app is that the service provides 'very good' suggestions on the homepage based on prior browsing. I am running on Android 6 and everything is working perfectly fine in the official YT app when I use AdClear (without Dubbel). I was checking their site and observed that Dubbel is only required for effective adblocking on Android 7 or higher. This technique eventually will fail to work too (when I don't know, depends when apps are updated), as apps target API level 24 and newer. Unfortunately even doing this doesn't allow AdGuard for Android to filter the YouTube, Facebook, Twitter, etc. In Android 7 and newer, apps that use API level 24 or newer don't trust user certificates anymore and the only way around it is by rooting the device and moving AdGuard's certificate from the user store to the system store, allowing more apps to work.

It works this way because the sandboxed YouTube app's traffic is piped through Parallel Space and because Parallel Space doesn't currently target API level 24 or newer in Android, so it still trusts user certificates which allows AdGuard for Android to filter Parallel Space's traffic (and apps sandboxed inside of it).

This method is a bit cumbersome to setup and annoying to do (versus installing an app like YouTube Vanced or NewPipe). You can already use this technique with AdGuard for Android and Parallel Space, which allows AdGuard for Android to filter the YouTube app that way.

I did a little research and it looks like AdClear does this by using Dubbel, an app that allows you to run multiple instances, which is similar to other apps like Parallel Space.

Adguard youtube ads