The more general issue about state has come up before, e.g. https://lab.civicrm.org/dev/core/-/issues/724 and https://lab.civicrm.org/dev/core/-/issues/1709.
It's not a full solution but you can manually update the abbreviations in the database in the civicrm_state_province table, but you'd have to change the column size in the table definition, and someday ...
Thanks to @samuelsolv for his answer to Export contact info from MailChimp
Apparently, the separator for import/export of csv files is a "localization" setting, at this path: