The full freeze marks the period shortly before the actual release. Packages wanting to get into Bullseye now need a manual review by the release team to proceed.
Debian 10's full freeze began in March 2019 while they released in July. Or with Debian 9 the full freeze was in February 2017 with then releasing that June. So we'll see how long it takes before Debian 11 gets a formal release date but more than likely will be in the next three months or so.
More details on the full freeze for Debian 11 via the mailing list .