Why blocking on its own stops working
Almost every gambling app is a blocker, and a blocker is a decision made in advance, while you are calm.
That is a genuinely good idea and it is why they exist. The problem is structural: the urge does not arrive while you are calm. It arrives afterwards, at 2am, with your full intelligence pointed at getting round the thing you set up. A new site, a different browser, someone else's phone. You know the route because you built the wall.
A blocker manages your access. It does nothing about the thirty minutes where you are deciding again.
Paddle Past can block apps too, on iPhone. The difference is when you choose. You pick the apps and the length while the urge is happening, not weeks earlier. Then it does what it is really for: six minutes, and then you decide.