Hey suspectedlake0
From what you’ve described, I’d avoid unlinking or linking the PlayStation/Xbox accounts to another EA Account for now.
In Apex Legends, your progress, cosmetics, and other content are permanently tied to the EA Account they were earned on. If a platform account is linked to a different EA Account, the old Apex progress doesn’t move with it. If it’s linked back to the original EA Account, the progress should still be there.
Since you no longer have access to the email address on that original EA Account, the best next step would be to contact us via chat and explain that you need help regaining access to the EA Account associated with your Apex progress. They can look into the account-specific options available to you.
https://help.ea.com/en/customer-care/
You can find the Cross Progression information here
https://help.ea.com/en/articles/apex-legends/cross-progression/