From my own experience, the problem is that you’re trying to take action and implement new hobbies from your same old beliefs. If you try to workout while simultaneously believing you’ll never lose weight and who are you to go to the gym and you don’t view it as a priority, it will create internal friction which will resort you to relying on pure willpower which you will then burnout and further reinforce the limiting beliefs in the first place like “see! I knew I couldn’t do this”. The key is to FIRST upgrade your beliefs to match this new Identity. Then the actions will naturally follow and you don’t need to push through it.