If your Xbox and Steam were linked to different EA accounts then it would not be possible to merge them, even if one has been relinked from one EA account to another.
You will be able to access progress that was made on the EA account it's currently linked to, but not from the one it was unlinked.
So how will i be able to play on my xbox account on pc
An EA Account now holds one main merged account, rather than separate accounts for each platform.
If all your platform accounts are linked to the same EA account, then you would be able to access this content by just logging into an account.
So in your case, you can play the game via Steam or the EA App and access your Xbox content on PC.
