I have the same issue, I have the account pro. Neither 5.3 and 5.4 able to use.
Bring back 5.3 codex Open Ai.
Bring back 5.3 codex Sam Altman.
So now it’s not worth to try it. 5.2 is a joke today…
I have the same issue with GPT-5.4 and GPT-5.3-codex.
Bring back GPT-5.3-Codex Sam Altman!