I'd like to offer a slightly different perspective. My friend is married to a man who collects plastic crap. Things like all the starwars figures, thousands of dvds, etc. So no rubbish, all technically reasonble even expensive stuff.
He also has ASD.
They live in a modest house, and it is FULL of his stuff. The living room walls are lined with shelves full of the dvds, one of the bedrooms, all the attic etc. And is creeps into the rest of the space. About 10 years ago, she was feeling like you, drowning under the amount of plastic, and it just kept coming in, everyday parcels would arrive. There was no space for any of her stuff, her hobbies, and she, like you was cleaning out and downsizing her stuff and their dc stuff in order to create space. But his stuff just kept growing.
The thing she found hardest was that he could not see at all that her needs were being overshadowed by his. It got to the point after about 8 years together, where they went for marriage counselling and basically, if they didn't have a breakthrough, then she wasn't sure she could continue.
It was painful and hard, but through the counselling he did finally understand why she was struggling, that her needs were being swamped by the parcels in the post.
But also they were able to talk through how he felt about his stuff and why it mattered. I think the ASD is really, really relevant here, his things make him feel safe, they are predictable, they don't have complicated human emotions, they are safe and being surrounded by them makes him feel that his world is a safe space. He adores his wife, but he literally does love his stuff in a way that someone on the outside just cannot understand.
To ask him to get rid of stuff was like asking him to cut off a hand or a foot.
But he did understand the problem, and he did promise to start to reduce. He began with the loft and has been box by box reducing his collection. That was 10 years ago, and until the last 6 months, it was still going, slowly reducing bit by bit. But as 2 boxes left one new parcel arrived.
They did come to an agreement about where the collection lived, and he has stuck to that, it has not crept anymore, and it has been reducing.
6 months ago, they decided to move. That was the last push he needed, in the last 6 months, loads of stuff has gone,and what is left is now a curated collection. He has one room, lined with display shelves and storage boxes in their new house, the rest has gone.
It took 10 years, and he was not a classic hoarder, and he agreed to change, and he has been working on it, and he has stuck to the boundaries they agreed, but still, 10 years.
But I find the ASD side of it very interesting, and I think it helps us to understand them a little better.
OP, your feelings are valid. and please don't ever think that they are not. I could not live in a house that was not visual comfortable to me. Fo me that is things like clashing colours, for you it is clean tidy space. Your need for that is 100% valid. someone upthread described it as visual noise, and that is exactly it.
It is OK to have feelings and it is OK to insist that your feelings are as valid as your partners needs.