3.11 is more "stable" in the sense that it will change less. but I would consider a new CPython release to be fine for general use as soon as it hits .0--that only happens after about a year of alphas, betas, and release candidates (
https://peps.python.org/pep-0693/ is the 3.12 release history and schedule)
(Of course, not every library is ready to go as soon as .0 drops, but there's a lot of backwards compatibility)