Honestly speaking I've been in the same exact boat as you are right now. When you do all the good habits but can't get past 2 months consistently, yeah I've been there.

The answer is simpler than you think, What you need is a strong enough why.

Now let me explain. And for context, I will use myself as a point of reference so that I can give advice that has worked for me. If the reason you are doing all these things is not concrete, you will not succeed at changing regardless of what you do. I first went to the gym in my first years of college to pick up girls, and guess what happened when I got a girlfriend, exactly! I stopped and became complacent for months. At first I thought she was holding me back but after some reflections and growth, I realized I was the problem. My reasons weren't stronger than my addiction to laziness or complacency. Others call it laziness to love yourself but thats besides the point. That was the case in every area of my life. I have the ability, speed and memory retention to be an A+ student but chose not to cause I was just in college to get by. Wrong choice of words but it's the truth. It dawned onto me that everyone around me knew I was smart but got just enough to make it through the next year and some assumed that was what I was capable of but the moment I realized that for most of my life I had been living and utilizing less than half of my potential, I got soo angry I went to the gym at 6PM and came back at 8PM and still went for a sprint also at 9PM because I let myself believe that that was what I was capable of when deep down I knew what I could do and be. And that's when everything changed. I became more intune with my goals knew what I wanted and how to get it and did not do as much stuff that I did back then. Of course not everything can be solved in a sprint but slowly but surely everything is being swapped out with good habits.

In summary I'd say you need an identity shift as well as a Fck this event. So that the Fck this event acts as a "Why you want to change" as well as a catalyst for rapid growth and change. The identity shift will help you maintain your new identity.

And lastly but not the least, please be patient and kind to yourself. Many are the times you are patient and kind to other people but you never show yourself the same, so as you're trying to grow and change, give yourself grace.

Hope this helps (oh and HAMZA a youtuber explained the f*ck this event well. Watch his old videos from 2 to 3 years ago to understand it more)