"Against" is the wrong frame, and it is why so many apps fail. You install a blocker, feel in control for two days, then hit the wall during a real craving and tap right through it. Or you uninstall it. The scroll wins because the app only said no, it never offered a yes.
Why "against" usually loses
Doomscrolling is an automatic habit. Your hand moves before your conscious mind has a say. By the time a blocker shows its wall, the craving is already running, and willpower has arrived too late. Worse, blocking the app does nothing about the feeling that sent you there, the boredom, the stress, the avoidance. Take away the scroll and the need is still standing there, looking for the next thing.
What works instead
The apps that actually move the needle do three things a wall cannot. They interrupt the autopilot gently, with a beat of friction or a breath, before the feed loads. They offer a real alternative that meets the same need, a walk, a message, a moment outside. And they learn which alternative works for you, so the better choice gets easier over time.