I am a US citizen planning to marry a German citizen. I am unvaccinated but hoping to travel one way to Germany to marry and live with my partner. Our registration of marriage is currently being processed at the Standesamt and may take up 6 weeks. Is it possible to enter Germany with only proof of a long term relationship if I intend to stay more than 90 days? Or do I need my fiancé to mail proof of the engagement to me?