I am engaged in writing texts on various topics. But since I have been working in this field for a long time, sometimes I repeat sentences or the style of writing. And I need uniqueness. What to do?

I think initially you just need to rest and that will be all. The brain itself will begin to work in the direction in which you need. Also, as an option, you can try to use ai paraphraser. They say it's no problem at all to write anything with it. For more information, see https://pr-cy.io/rewrite/. I think this is your option.