PEP 292's `string.Template` will remain; there are no plans to deprecate it.
PEP 750's `string.templatelib.Template` is a separate and unrelated type. Amongst many differences, unlike PEP 292, `Template` has a literal form too.
I'm hopeful that the confusion will be minimal; in practice, PEP 292 (aka $-strings) is used only in specialized cases, like flufl.i18n, a really deep I18N framework.
[1] https://peps.python.org/pep-0292/