Congrats on sobriety and sharing some of your struggles. I remember when I first had the desire to build a business, I probably spent a month going in circles thinking about all the different problems I was going to need to solve and tools/languages I was going to need to learn. I never really made any progress, so I decided to focus on just the name of the business and then buy the URL. It might have been premature since the business wasn't figured out (I ended up changing it later), but having a name, at least let me mentally move forward with the product and design.

I haven't spent much time thinking about my purpose in life, but I think I would approach it in a similar way. Take small steps (e.g. talk to someone new about what they love in life, rediscover an old hobby) and trust that the steps will build over time into your ultimate goal.