I have the same problem as you. I'm stuck in the mud again, floundering and barely getting anything done, and searching for an answer. Currently not in therapy so it starts to have that shimmer of 'external solution' when I know, deep down, the problem and the answer lie within.
Thinking disease? Then start with practicing non-thinking. Meditation…quiet the mind…listen for your inner voice that has infinite wisdom. I hear mine saying "Stop with the porn. Scrolling reddit is depressing you. Just stop for 2 weeks and listen to music instead. It's warm out today, go for a bike ride…." And if i just listened to this voice more, if I truly planned my days around what I truly think instead of just reactive patterns and scattered thinking, I'd probably be in a better headspace… maybe even a better physicalspace.
I think to be a simpler man, a man of action, with less thought, just make your thoughts more high quality and reduce the frequency. So all of the self-help stuff talking about journaling in the morning, writing your daily pages, doing the meditation and stretching or long walks in the woods — you actually do them and glean what they provide. A man of little thought might think for an hour, and then act for 9, with singular focus from that disciplined forethought. I think there's also an aspect of accepting limitations of what you can reasonably accomplish each day… then doing it day after day after day… and seeing the remarkable results. When we give our minds impossible problems, it can just ruminate forever without ever lifting a finger. Maybe a figure to look towards: Richard Proenneke
https://www.youtube.com/watch?v=PaBxxl6ZTTE From personal experience, if you think you might have ADHD or depression causing the mind sprials, psych meds can be helpful to start untangling those patterns. With mindfulness practices you can internalize and observe the effects of the drugs, and memorize the behavior patterns for future reference as you grow older if you are into that kind of mind wizardry. ADHD meds helped me through a difficult patch where my mind spiral was going to cause me to fail in my senior year of college so I chose to medicate with ADHD meds and got through it, got my first job several months after graduating, and started a meditation practice every lunchbreak for 20-30 min when I took my afternoon dose. I could actually observe the effects on my visual acuity and mental focus, trying to permanently etch the state of mind into my neurons. I didn't want to take these meds forever, but i deseperately needed a taste of what it felt like to exist with ability to concentrate and achieve things… It was honestly surprising to me that I was able to put in 8 hour days of focus at my first career job in my mid-20s given how scattered and broken I felt before and as a teen. I didn't think I was capable fundamentally. Honestly, the feeling of being on those medications made my brain actually feel like it wasn't constantly working against me. Your milage may vary, but it was crucial for me. But then again, now currently in my mid 30s, unmedicated, with same old problems. But I do think having the memories helps me get out of the ruts quicker, so I waste weeks instead of months or years now.