Thoughts on the Mahdi Hadith: Do we need a Caliphate first?

Assalamu alaikum everyone, I came across this well-known hadith in Sunan Abi Dawud (Book 38, Hadith 4286) from Umm Salamah about Al-Mahdi, and it got me thinking. The hadith describes a situation where a caliph dies, and there's a disagreement among people, then a man from Madinah flees to Makkah, gets pledged allegiance, and armies are sent against him but swallowed by the earth. Since the Ottoman Caliphate ended in 1924, we don't have a single caliph for the whole ummah anymore-just separate countries. So I've been wondering: 1. For this scenario to actually happen, do we as humans have to work to bring back a proper Caliphate first, so that there's a caliph whose death can spark that crisis? 2. Or did scholars interpret 'caliph' here more loosely-like maybe it just refers to any local ruler, or does the Mahdi himself set up the system later? If anyone knows what scholars like Ibn Kathir or Al-Qurtubi said about this, or recent hadith experts, please share. I'd really appreciate it. Jazakum Allahu khairan!