DeadDakotah If relinking back to your old EA Account didn't restore your Apex progress, there is sadly no way to restore the missing Apex progress.
Furthermore, unlinking accounts in general does carry a risk of data loss as well:
Unlinking risks for Apex players
If you unlink a platform account that you use to play Apex Legends, you might have issues with Battle Pass leveling, item unlocks, and other errors.
Instead of unlinking and relinking a platform account you play Apex on, we recommend starting fresh on a new account.