Fdwish Your Apex progress is stored on your EA Account, (not on PlayStation or on Steam), and while there is Cross Progression, there is no merging of accounts as that was only possible during the Cross Progression merge for platform accounts, (which was between October of 2023 and April of 2024).
Switching platform account links around now also won't transfer, (or merge), your Apex progress.
Its also not possible to transfer, (or merge), progress between two EA Accounts.
ApexYy0918 Your language is sadly not supported on the EA Forums, however after translating it, it seems that you are having issues with unlinking your platform account due to being unable to sign into the correct EA Account, and for that, you would need to contact EA Support: