Du support US : "Yeah there are several cases for similar issues in the past hour. I'm sorry to hear that you're having issues with connecting to Steam to your Origin account. Do not worry, I'm here to help. I would like to inform you that we'd received many reports about this issue already. We have forwarded the information to the Origin and Steam team and are waiting for an update. At this point we appreciate for your patience while we investigate what's going on. There are hundred of requests where a player wants to unlink or link their Steam from Origin account and we're still in the process of manually implementing a system on the player's end for this. They also getting an error while linking the accounts.
Though, our team and Steam team is dedicated to this issue and it'll surely get fixed soon. I can guarantee you'll be able to link or unlink your Steam account from your Origin, you can mark it. However there's also a possibility it may not be unlinked now, still we can't jump on any conclusion as it's being worked on. In this case, we appreciate your patience for sometime. You'll be able to link or unlink your accounts soon as we may introduce a feature for it on the player's end and fix this ongoing error while linking.
It is not the problem, once Steam is linked with Origin it can't be unlinked as it is not about Apex. There are thousands of cases to unlink Steam from Origin. So waiting is the only thing. I could've suggested something here but it won't work. Don't worry, considering the number of cases, it shouldn't take that long to be fixed considering the number of the cases we're getting."