Dilemma with Partition Key choice
Most queries become slower with partitioning.
The exceptions I know are:

a query that needs a sequential scan, but contains the partitioning key in the WHERE clause
a query that joins two partitioned tables, and the join condition matches the partition key for both
a query that groups and aggregates by the partitioning key

So you should rather consider how data expire. Partition your tables so that you can get rid of old, obsolete data by dropping partitions.