Debian 12.0 "Bookworm" Looks Like It Will Release Around Mid-2023
Debian is normally on a two year cycle between major releases of their Linux distribution and this should be the case for Bookworm or slightly less depending upon how things play out post-freeze.
The Debian Release Team has proposed their transition and toolchain freeze to happen around 12 January 2023, the Debian 12.0 soft freeze for around 12 February, and the full hard freeze to happen around 12 March. The actual Debian 12.0 release would come sometime after that point, usually within a couple months, depending upon how the bug situation plays out. But in any case it looks safe to expect around a mid-2023 release of Debian 12.0.
The tentative dates were laid out in this mailing list post though it seems they mean 2023 for all the dates, not 2022.