Assume you don't have a purpose.

There is one piece of advice you will hear a lot: Find your purpose in life. How to do this you will never know. The only thing you will hear is that you'll know it once you see it. This isn't helpful. Ignore this advice.

There are many people who found their true calling. The musicians I find inspiring want to improve their music making for the rest of their life. If it works for them, that's great. But it's not the only way to find something meaningful. Look at Leonardo da Vinci and how many things he dabbled in. He didn't find his one true calling. Assume it doesn't exist for you either. And pick your approach based on that.

You might be dreaming of all kinds of things. This kind of daydreaming is fun. But it will also be depressing if you don't start working towards any of these dreams. So start a list of all the things you dream of doing. Each month, pick one item from this list and create a project around it. See if you like it. You might realise that what you dream about isn't that exciting once you start working on it. That's to be expected. There will always be things you wish you knew but don't actually want to learn. But you will never know this if you don't try it. If you encounter such a thing, pick a different item for your next project. But if you liked spending time on your previous project, do another project in the same direction. Repeat this ad infinitum.

In the moment, doing what you already know will be much more enjoyable. Repeating the same riff you already learned will be more fun than learning the solo that's just a bit too challenging right now. But if you never go to the end, never learn a song to perfection, playing guitar will become a drab. So use these projects to challenge yourself. Even if it's not as fun in the moment, deliberate practice is the meta skill that will set you up for success.