You're lucky I've got 0.129.0-alpha.9 on my MMM4Pro in Xcode RC 26.5 but I can't get it on my MBPM1P in Xcode RC 26.5, but 0.120.0 is fine and signs in. on the MBPM1P in Xcode 26.4.1, I can't sign-in with that tho...
So in summary on the:
MacMini M4 Pro signed in to 0.129.0-alpha.9 and Codex 5.5 picked (Xcode RC 26.5)
MacBook Pro M1 Pro signed in to 0.120.0 and Codex 5.4 picked, (i.e. can't get alpha.9 so can't get 5.5! even tho Xcode RC 26.5!)
My problem I think is I didn't upgrade the Codex on the MBP before doing the macOS RC 26.5 + Xcode RC 26.5 (Like I did on the MacMini).
And since I didn't upgrade in Xcode 26.4.1, when I did the full RC cycle, when I launched Xcode RC 26.5, it upgrade the Codex Plug-in but stopped at 0.120.0! On the MBP+Xcode RC 26.5
UGH 🤷🏻