Thanks for the answer, @Asmodeus566
I just explained the whole situation, I don't want cross progression for Apex Legends.
My Apex Legends progress is on the "Second" account, and I unlinked my steam from "Second" and then linked it to "First".
My problem will be solved if I can unlink my steam from "First" and link it to "Second" again. but because I did this unholy linking deed xD two days ago, now it says I can't unlink my steam for 6 months.
This way I will not play Apex Legends anymore, after playing a lot for 3 years.
1. If possible, I want to combine my account like it's indicated in https://help.ea.com/en/help/account/accidental-second-ea-account/
2. If combining is not possible, then I just need to unlink my steam from the account that I linked it to two days ago, and link it back to the account I have all my cloud save on.