It is only pyright/basedpyright that flags Optional[T] as deprecated as far as I am aware. Optional isn't actually deprecated by Python or anyone else.

You can disable it in the pyright settings. In my opinion T | None is not a meaningful improvement and insisting on changing it everywhere causes a whole bunch of churn and needlessly makes code stop working on older Python versions.

Optional[T] was always just an abbreviation for Union[T, None], anyway: it's unsurprising that they didn't choose to give it its own syntax.