I use the Mac app Focus for this, even though you find it gimmicky I have it set up in the same way as you do on the most part.
I have a whitelist, rather than blacklist, so only sites that are related to doing productive work are allowed as well as apps. But the application has a break feature, which gives it out in five minute chunks, so if i want to stop and look at anything other than work, I have to go into the menu bar and select break and then i get five minutes.
Once that is up, it resets and I have to go back in and do another five minutes, this limits my time and makes me more aware. I can also set a max time for the overall amount of five minute chunks I am allowed if I want to get more restrictive.
Timers seem to be the key for me with anything though to be honest.
I have a whitelist, rather than blacklist, so only sites that are related to doing productive work are allowed as well as apps. But the application has a break feature, which gives it out in five minute chunks, so if i want to stop and look at anything other than work, I have to go into the menu bar and select break and then i get five minutes.
Once that is up, it resets and I have to go back in and do another five minutes, this limits my time and makes me more aware. I can also set a max time for the overall amount of five minute chunks I am allowed if I want to get more restrictive.
Timers seem to be the key for me with anything though to be honest.