How far does one table, one query go?
The “one table per query” thing is a misnomer - the real practical advice is to figure out what you need to read, and then store data to serve that purpose

Sometimes that means fully denormalizing your data, duplicating columns between tables

Sometimes that means lookup tables that act as manual indices - whether you denormalize or use a lookup table depends on which is easier for you, the extra query or the extra storage cost. That’s a personal decision.

10,000 items in a partition is probably fine unless their large blobs (try not to hit 100mb/partition), but do try to take advantage of clustering for queries where you’ll fetch multiple rows.