Apache Flink

In Flink, is there a way for an upstream `ProcessAllWindowFunction` prior to `keyBy` to share state with a downstream `ProcessWindowFunction` post `keyBy` ?

I am trying to achieve this without `EmbeddedRocksDBStateBackend` since I need to just store very small data.
I was looking at `BroeadcastState` and `OperatorState`. Am I in the right direction?

It seems that I cannot use ProcessWindowFunction with BroadcastState.

*<https://nightlies.apache.org/flink/flink-docs-release-1.15/docs/dev/datastream/fault-tolerance/queryable_state/|[Queryable State] >*might be something I am looking for.