Confused as heck as to how account linking works

So long ago i used to be an Xbox player and while i was i decided to play Apex Legends but if i wanted to play it i had to make an EA account, so i did and i linked my Xbox Gmail to it.

but now years later i am a PC gamer, so im confused as to how i'd go about linking the two accounts? do i unlink my steam account from its own EA account? and link that one to my xbox one? 

or do i do it in reverse, and unlink my Xbox account from its Own EA account and link it to my new steam one? i wanna make sure i am able to keep my XBOX progress that i had on Apex Legends, and i also wanna make sure i am allowed to continue to play Rb6 and other games without it saying i'd need to rebuy it. 

how would i go about doing this? without losing any of my Xbox account progress?

i dont really care if i lose the little progress i have had on steam, i just wanna KEEEP my XBOX PROGRESS.