Wasn’t it mentioned somewhere that statehood cannot be revoked for any state unless the state wanted that?
If the Court were to just straight-up find that the granting of statehood in & of itself was unconstitutional, then that would be the end of that, previous precedent be damned.
Isn’t unconstitutional to remove a state, or was that just a norm?
It is unconstitutional to remove a state if they are rightfully a state, but if they were never really a state in the first place their statehood could be revoked. Some really hardcore originalists have argued that West Virginia is not "really" a state, for instance.
Didn't Barrett herself basically say that, except for West Virginia she thinks its statehood is such a 'superprecedent' that the Court can't and shouldn't overturn it. A factor which wouldn't apply with DC statehood.
She did co-author a piece which noted that there are originalist arguments to think that WV was invalidly admitted as a state (among other weird conclusions), yes, but to be fair to her, the paper didn't accept those conclusions except for the sake of the hypothetical argument therein.