For the first 3 hours from 9:25 am to 12:17 pm (US late evening time), only 748.1K ( 897.9 - 149.8 ) Twitter users followed Trump's account.
However, at 6:31 pm ie the US time 05:36 am, there are ~59M Twitter users following Trump.
I believe most of Trump's followers are Americans. These massive new followers should be reinstated at the back end by Elong Musk, not voluntarily joined by Twitter users themselves.