South will reopen when BA make a meaningful return to LGW. Without BA's sizeable operation and Norwegian's 787s, which accounted for the bulk of South's activity, there's no need for it. They've only just reopened Pier 6 in the North Terminal.
Last Friday was the busiest day in terms of outbound passenger numbers since March 2020, however it was only a few hundred more than the busiest day of last Summer, had fewer flights than the busiest day of last Summer, and was about a fifth of the number of passengers on the equivalent day in 2019. A long way to go.