Dear @liebenleben,
It is not possible for her to apply for a residence permit while in the asylum process. She will remain with the status ‘Aufenthaltsgestattung’ until a decision has been made on her asylum application. In addition, the type of residence permit you have (deportation ban) is generally determined in the asylum process by BAMF. If she were to withdraw her asylum application, she could apply for a different type of permit, e.g. family reunification with you. However, it is rare that a family reunification permit would be granted to the spouse of a person with a deportation ban. In my view, I do not see any advantage in withdrawing her asylum application. If considering doing so, I recommend you seek legal advice before doing so.
Best,
Éanna