#30426 introduced queryable primitive collections, producing inline and parameter query roots in the query preprocessing phase. This was fully implemented for relational, but Cosmos and InMemory support wasn't implemented for timing/prioritization reasons. As a result, inline and parameter query roots are opt-in (and relational does this opt in, see #30966).
We should always produce inline/parameter query roots as a standard feature of the query pipeline, and adjust Cosmos/InMemory accordingly. This doesn't (yet) require actually implementing full primitive collection queryability for these providers - just make them work as before.