I've seen people use Screen Time on iOS to help them 'adjust' their behavior. There was a thread on this just the other day: https://news.ycombinator.com/item?id=48312443
I noticed this made a huge difference, I'm much more focused on training and my gym sessions finish a lot faster.
That limits the ability to use it (or buy it) in any «unsupported» country.
I'm looking for a dumb phone and this looked promising until no email. Email is underrated as a time saver, if you aren't getting hundreds of emails daily which is a choice. Email is not as urgent as text or phone calls and its main advantage is that it separates the sender/receiver schedule or timezone.
People need to learn to guard their time and schedule like a hawk and not operate in chronic reaction mode, i.e. someone else setting your priorities for the day.
Why not just use a smartphone if you’re able to guard your time effectively?
I feel like the main reason people are interested in dumb phones is because they’ve identified that they personally can’t, for whatever reason. (Certainly that’s why I’m intrigued by them.)