Not the parent post, but working in finance, multiple products had a "scrambling" feature which replaced many fields (names, addresses, etc) with random text, and that was used upon restoring any non-production environments. It's not proper anonymization since there are all kinds of IDs that still are linkable (account numbers, reference numbers) to identities but can't be changed without breaking all the processes that are needed even in testing, but it's a simple action that does reduce some risks.
I get changing passwords, but say that data leaks (whether by a vulnerability in the clone environment, or by a dev gone rogue), how do you mitigate possible damage done to real users (since you did clone from prod).
I ask not because I question your actions, but because I've been wanting to do something similar in staging env to allow practical testing, but I haven't had the chance to research how to do it "properly".