There are strategies that tend to have better success rates than others—and to be clear, I think this blog post gives good advice—but I'm suspicious of any "successful" strategy that is merely the most recent in a long line of attempts.

I think people change slowly—much more slowly than we usually assume. Every time you try something to fix your life and you fail, you actually make a little bit of progress on yourself, just not enough to switch your behavior into something recognizably better. When you try a new strategy and succeed, there is a strong chance that you would not have been successful had you not made all of that incremental progress on yourself from all your failures. That's why it's important to never give up on yourself.

I've had "breakthroughs" that were basically just me trying the same thing I tried (and failed at) years earlier. The difference was that I'd gotten stronger in subtle ways over that time. Then, 6 months later, I'm back to my old habits. This is depressing, but when I remember that this is the first time I was able to stick with something for months instead of weeks, I realize I've actually made progress on myself.

Even though this isn't strictly about productivity, I think the best lesson from OP is that things get easier as you practice them. This seems obvious, but when we talk about building skills, we often frame it as us rising to the challenge. I.e., there's this very hard thing we want to do, and we need to become stronger to be able to do it. This isn't wrong per se, but I think it's bad for motivation because it frames progress as doing as doing increasingly more difficult things. Instead of thinking about getting better, I think it's more helpful to frame progress as things becoming easier. No matter how weak you feel you are, the things you find difficult in life will become easier as you work on them.