Was the device registered to the work network using a device management system? Was that MDM removed? If it was not removed, did it at least use the work profile configuration?
If it was simply a phone in phone usage only, they wouldn't have had access to that info anyway. If it was registered with an MDM and that has since been removed, they would no longer have access. If it was registered with an MDM and it used the work profile, they never had access to the personal side anyway.
If you're really concerned - sign out of ALL accounts, wipe the device and set it back up from scratch with your personal account.
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