This is a a microcosm of so much addiction, at least in my experience. Friction really matters in giving your mind a moment to pause and consider. I think adding friction by getting a less capable phone is a great technique, similarly to how I'd hide the candy/alcohol/TV remotes if folks in the house are addicted. It doesn't remove the opportunity, but it makes it tougher.
This happened for me as well. It adds insult to injury that lying awake, unable to sleep properly for months straight, doomscrolling (or just being online too much) further saps your mental health in an already drained and depressed state.
It's a pretty messed up negative feedback loop. If you find yourself in this state, audiobooks are a good alternative.
I've tried a number of different things but nothing stuck. I've had this phone for a few months now and it has really done the trick.