I have AuDHD and spend 80% of my waking moments ruminating, processing, overthinking etc. When it gets especially intense I find myself stuck in Freezes that last hours, days, weeks. I've found that getting out a blank piece of paper (it cant be within a journal/notebook for some reason) and writing down everything on my mind - from to-do lists, things I want to buy, outfits I want to try, routines I'm trying to figure out, and/or interpersonal dilemmas - leaves me feeling so much lighter. I also get clarity around questions I'm mulling over.
I had an especially illuminating Brain Dumping session yesterday and I feel like someone just took a swiffer duster and cleaned every nook and cranny of my brain. Or a system reboot.
Also - I suggest trashing the brain dumps after a certain time and not try to turn it into a rolling to-do list. If you don't act on something within a few weeks, and you're still not thinking about it, it likely wasn't that important, and your brain will thank you for decluttering.