If something takes willpower, then you're not going to be able to keep it up for life. You only have so much willpower, and inevitably more important things crop up in your life - things that demand all of your willpower right now.
So either it becomes a habit (and stops requiring willpower), or you need to find another magic wand
By all means commit to try to use your willpower to try to make a change in your life for a set period. But, if during that time you fail to keep to your commitment - or if at the end of the period youi feel proud of yourself, but the idea of another period just as long fills you with dread - then give up using that approach.
If it still takes willpower, it isn't a habit.
But just because it doesn't work now, doesn't mean it won't work in the future. You change, your environment changes, your options expand and you learn new tricks, new ways of doing things, special sauces you can use to make your challenges super tasty. Now you have two magic wands to search for
A wand which will solve the original problem without requiring so much willpower
A wand which will make using the wand that didn't work last time work better this time
Thats twice as many possibilities - you've doubled your chances of solving the problem