If you have existing Zarr data you want to expose for read-only use, and you’d like to reduce the file / object count, a great option (which does not require sharding) is to put it all inside a zip file. You can read from this zip file concurrently with no performance penalty.
If you want to continue writing to the store, the sharded Zarr V3 format would probably be a better fit. Support is not fully implemented yet in Zarr python, but it should be here soon.