that doesn’t work for twitch unfortunately :(

there used to be a different Firefox extension for just twitch which worked but idk what happened to it.
The way it worked was by taking the tiny steam of the creator that shows up when an ad plays and just scaled it up to cover the ad while muting it.

I’m sure there is a way to prevent this screen in particular, but IIRC Twitch simply doesn’t stream to you when there’s ads playing, or it’s hardcoded into the stream itself or something, so you’d be looking at a small audio-less preview if anything … & correct me if I’m wrong. I stopped using Twitch entirely because of this, though.