I favour annotations for type hints; the writing's been on the wall for some time. I think the necessary escape hatch for those using it for other purposes should be Annotated[Any, ...] (or a similar, nicer alternative).
Guido, one of the difficulties I'm having is understanding the direction you're going with "relaxed syntax". PEP 649 is concrete; it's hard to weigh its merits against the usability—even feasibility—of incorporating an as yet undefined relaxed syntax.
At the end of the day, such syntax is going to have to be represented in some structure. If one were to accept that annotations are for type hints only, is the debate then the difference between a Python type (which PEP 649 would yield) and some other as yet undefined structure?