Hey @ManInTheBox404,
While you'd be able to unlink one platform and try re-linking it to the same EA account, as you mentioned this will cause a loss in progress.
The progress and cosmetics you've unlocked are stored on the EA account, so if you have two separate EA accounts and a different platform on each, there won't be a way to combine that progress I'm afraid. One of those will be lost depending on which platform you unlink (if any).
If you're wanting to make use of Cross Progression on these accounts going forward, you will need to move one platform or the other to the same EA account. That won't bring content from your second EA account, but you would have access to your main EA account content on both platforms from that point forward.