Rewrite text to match my voice without making it sound like AI wrote it

I write a weekly internal newsletter. When I run drafts through a model to tighten them, the output is cleaner but reads generic: every sentence the same length, transitions like "moreover" and "in today's fast-paced world", and all my odd phrasing sanded off. I can give it 2000 words of my previous newsletters as a sample. What I want is edits that fix actual problems (buried lead, unclear antecedent, a paragraph doing two jobs) while leaving my sentence rhythm alone. Ideally it would show me what it changed and why, so I can reject the ones where it is wrong. Everything I have tried either barely changes anything or flattens the whole thing. Is there a prompt structure that gets a model to edit conservatively?