Must one who desires to obtain the full reward of 'Umrah in Ramadan (which is equivalent to Hajj) be present in Makkah from the first day of Ramadan?

The virtue of Umrah in Ramadan is immense, as the Prophet, peace and blessings be upon him, said: "When Ramadan comes, perform Umrah, for Umrah in Ramadan is equivalent to Hajj." And in another narration: "It is equivalent to a Hajj with me." This reward is obtained by anyone who performs Umrah in Ramadan, whether at the beginning, middle, or end of it.