Hi, and welcome, I've been a long time user of this app, and I've also experimented with several others that operate the same exact way. Non of them are very effective against ads on streaming services, like YouTube, Terrarium TV, or others. The way these blockers filter ads it is difficult to intercept URLs from streaming services. Even Adgaurd had problems back a few years ago, blocking ads in YouTube. The way they got around this, is by intercepting Https, decrypting, then can block specific URLs. That's one of the reasons they charge subscription. It's also, not very privacy friendly either. Some of these blockers that filter DNS do so locally on the device, others, through a server, like Block-This does. So, sorry, but if you use these types, you will have to put up with a few ads. I do think they block some if the pop-ups and banners in terrarium, which otherwise, would be too much for me, so, do run block-this when using it.
Also, you might want to check permissions for terrarium TV, and turn off location, and contacts access. Because, advertisers can get that info too, just from using the app. Happy blocking!