Looking through the SE-Service Account options, there is no obvious way to change my region which clearly states "Americas."

So at this point, I don't know what to do outside of wait for SE to respond to my tickets (and not just close them without a response.)

For anyone not sure what I did:
US PSN ID couldn't claim the code that the pre-order site gave me.
Opening the P4 client prompt me to enter the 12-digit code, of course my code didn't work.

Switched to my EU PSN ID. I was able to claim the 12-digit code and downloaded a new client.

I switched back to my US PSN ID, and the new client wouldn't load (asked me to enter 12-digit code, which again didn't work.)

Swapped back to EU PSN ID, ran new client it opened up fine, accpeted EULA, then asked for my SE-Service Account info. I entered it in and got a nice new Error:
"This region is different. Please log into a region where you registered your Square Enix Account."

Back to trying to get the client to run from my US PSN ID. Oh god this has been such a pain. Guess I'll be missing Early Access at this rate, and now I got a code I have no idea what to do with haha.