Read digital minimalism, install pihole on your network, use Tailscale for DNS to point it there, implement blocks on the offending websites and categories. Make your smart phone dumb so you are limited to what you can do, and get an offline hobby.
Be easy on yourself, you will relapse, and realize that nearly everything on a digital platform can be shut off and ignored with the click (or long press) of a button.
Set up your environment for success, and make the path of least resistance align with your values.
You say you want one hour a day, but I’d scale back to nothing for a while and slowly re-introduce it. Or make it less convenient to do the activity.
This kind of thing works to begin with at least.. when that browser plugin in chrome stops me opening HN after 1hour it interrupts the impulse to browse, but then I can alway just open Firefox..
Limits outside ones control are best.. it's amazing how uninteresting youtube is when your data is rate limited.
Use a network level solution and don’t do a 1h block. Do a 365 day block to begin with. We’re like those rats with the cocaine button we keep pressing unless you can somehow disable it and go do something else with your time.
Given the amount of useful things and new perspective I get here, HN in moderation is a net positive on my effective use of my time. Blocking it outright for a whole year is a bit extreme. I might miss the news that pihole project was suddenly taken over by IBM or something.
I edited the hosts file on my Mac to send all these sites to 127.0.0.1... doing something means you're quite likely to know how to reverse it too though, hence why I'm writing this comment during the working day.