For me, being naturally messy is practically synonymous with being a packrat to the highest degree. Being a packrat is debilitating, especially if you live in a tiny flat in a big city that is very, very far from your parents' house in another country. Having storage space is not a thing, which means my storage space is in plain view, which means I am even more naturally messy than I was when I had a properly sized closet in the suburbs so I could mostly hide how messy I really was.
So. I must do a hard thing. I must sometimes throw things away. And if you're messy and don't have a massive basement of storage where you can hide your additional hoard of mess, so must you.
I say this as someone who still has three pairs of trousers she bought three years ago before she started working at a desk and keeps them with the firm belief that someday they will fit again. Some things are hard to give up. I get it.
But other things are only hard to give up because it's kind of comforting to have lots of stuff. Even if you trip over it on your way to the toilet every damn night.
Trust me on this: Round up the clothes you hate. Round up the books you've read and don't want to lend out or look upon with pride as you remember reading them. Donate them to Traid and Oxfam, or even to H&M, where you can get vouchers in return for clothing donations. Get rid of some of those eclectic mugs. Recycle all those half-used notepads.
The less stuff you have, the less mess you can have, and the less tidying you have to do, the better.