Therefore, no synod – with or without the Pope – and also no ecumenical council, or the Pope alone, if he spoke ex cathedra, could make possible the ordination of women as bishop, priest, or deacon. They would stand in contradiction the defined doctrine of the Church. It would be invalid.
https://www.lifesitenews.com/news/cardinal-mueller-no-pope-or-council-could-permit-female-deacons-it-would-be-invalid/