This information is not tracked anywhere.
If you wanted to do so you would need to create acf/save_post actions https://www.advancedcustomfields.com/resources/acfsave_post/ that run before ACF saves the value (priority < 10), and compare the existing data with the new data. Then, if something has changed you’d need to store the information about the user, date/time and what data was changed in other fields. There are no existing solutions for this that I know of.
