Does Madoka have any feats of beating acausal beings or preventing causality manipulation? If not it will be a draw since GER can't put conceptual being in a death loop but. GER might be able to revert her back before her wish though.

IIRC Kyubey described Madoka to be above the concept of cause and effect.

Madoka has no way to harm GER and since GER doesn't need Giorno to be alive to work even if Giorno dies he can bring him back to life or reset Madoka's action to zero.

Madoka cant have her wish reverted, the moment her wish took place it altered the past in such a way that it was as if she was always Ascended and had always existed past present and future.