I love that data connect supports {.._expr: "auth.uid"} to define server value based on Firebase auth token.

What about other CEL operations?

I want the ability to perform simple transformation using GraphQL variables, Firebase auth token and current timestamp. For example: _expr: "'hello from ' + auth.email"

I want the ability to combine data from different sources. Like execute a query and then use its result to perform another query or mutation. CEL expression can help cross reference data in previous steps.