None of those ways are sustainable. Not only because there are good reasons to use those apps, but also because there are times when forcing yourself to work isn't going to work. I mean, if I am sick, tired, and just not feeling like working, I would go out of my way to beat the system I installed.
What has worked for me is: one-sec extension [1]. The extension asks you take a deep breath and confirms if I still want to open the app. What I have realized is I don't want to completely do away with time-sink websites, I only want to moderate my behavior of pressing Cmd-T and opening reddit/youtube/twitter in the middle of work. I have increased the length of the pause to 30 second and I am actively forcing myself to actually take the deep breath. Such a pause is enough to knock enough sense into me and return back to work. I think such kind of gentle nudging is better than being overly harsh on yourself.
[1]: https://chromewebstore.google.com/detail/one-sec-website-blo...