Don't you get it? You wear diapers now. You USE diapers now! You aren't going to get to use a potty if you just hold it long enough. You're just delaying the inevitable. Full diapers are part of your life now. Messing your diaper is just how you go potty from now on.
That's why I slipped you that suppository during your last change. We need to get you used to your new normal. And that means going whenever you need to go. No matter where you are or who you're with. Even if it means that you're gonna be stuck in a full diaper for a few hours. No more of this holding it in nonsense!
There we go! Good boy~ That's it. There's no reason to fight it anymore. Just let it all out~
We'll repeat this as many times as we have to. Until you fully accept that using your diapers are a normal part of your life going forward. <3