NO NEW PROJECTS - YES! (caps emphasis for me - as someone mentioned above. I can't be reminded of this enough).
I've struggled with uncompleted projects for years, feeling like I never have enough time and energy...for anything. I would say my projects, both in number, and scope, are way smaller then what you have been up to, but for me, they're often overwhelming.
When we moved about 1.5 yrs ago it was a great opportunity to do "The Great Boyd Family Purge of 2017", and I'm still at it today. I sold, donated, and threw out tons of stuff, and even a number of tools and equipment that I don't really use. Lots of it was really valuable stuff and I'm realizing I'm not missing most of it at all. Quite the opposite actually.
And it feels great.
I had, I think 7 or 8 motorcycles, 2 of which were running at any one time. The rest sat and were just in the way. I also have an old Porsche project, its been sitting for 10 years. 10 years! I finally called a local Porsche friend and talked things over with him, we both agreed, its time to **** or get off the pot.
Not long ago, I spotted an old Suzuki GS1100, mint condition, priced so low I couldn't afford not to buy it. Mentioned it to a friend, he flat out told me, DO NOT BUY THAT. Would not give in to all my justifications. I didn't buy it and once it was gone from CL I actually felt relief. Called my buddy back and thanked him for being forceful with me.
That was a good lesson.
Ultimately, I had to decide what and how I spend my time. Its the only thing I can control. I'd rather ride motorcycles then restore/maintain them. I'd rather relax with family then (fill in x). I'd rather spend more on something newer that actually works, then spend less on another project.
Making lists and checking them daily has helped me prioritize. I don't always stick to the list, I regularly revise them, sometimes I ignore them. Its all good.
But my impulsive purchases and time ***** have almost been eliminated completely, its like a new way to live for me. Its not perfect by any means, but its way better then it was.
Good luck on your journey, I think its helpful that you're considering how you're spending your precious time and money, and what makes you happy, etc. So many people blindly run around without really considering what makes them happy.