A tool for tracking and recording activity within a codebase

Hi Everyone
I'm a co-founder at a start up. Interested to know if people have experience of a tool to tracking/record an engineers activity live within a codebase.

Our problem – high sensitivity personal data being handled, lots of new bugs to troubleshoot with new users, engineers currently limited to log reports and not able to access/view prod database.

I'd like to propose a solution a la Meta that turns on a recorder/tracker when some areas of the codebase/database are being viewed by engineers. We're not looking to track performance per se – we just want to make sure that where sensitive data is viewed it's clear that there's a record of this activity.
Does anyone have experience of any tools like that? Thanks!