How do you all update users without shifting historical information?

We have a lot of users that move from department to department or even from one division to another - promotions, position changes, etc.

We would like to update these users without changing historical information (timesheets, projects, tasks, role, layout template, dept., etc.). Additionally, we have SSO which means we cannot change the email address. Currently, we add an x to the name and email address and deactivate that user and create a new user with the same name and email from before. Thinking someone has done this in the past and has some insight into a better way to update a user but keep the historical data related to the original "user".