Seriously: Do NOT use similar-purposed blocker(s) along with uBlock Origin: this will cripple uBO's ability to defuse anti-blocker mechanisms and its ability to minimize likelihood of site breakage.

Thanks! I'll try that.

Try using only uBlock Origin (remove other adblockers), enable uBO’s advanced settings and third‑party filters, make sure Firefox is up to date, and if ads return after a day try disabling/reenabling uBO or reinstalling it — if that doesn’t help, ask whether this happens in Private mode or only on Twitch so we can narrow it down.

It seems to be just Twitch. The blocker works just fine when I'm in desktop mode, but it stops working when on mobile. It used to work on mobile fine, but after a day ads still kept on playing.