Shard drop rates very different

This is easy to get a misleading impression from these. The expected drop is between 1 and 2 shards, so getting one is not a "bad drop", and getting zero is almost as likely as getting three. But four and five shard drops are even less likely. And the reason the earlier star levels felt faster is because they required a lot fewer shards.

If you actually want to test, you need to record your drops every day across several months, and then go back and compare. No one can trust their intuition here, you need the actual data, because your brain will remember the things that made you unhappy (zero or one shard drops) more than the things that felt like what it "should be" (two and three shard drops). Even though 2-3 shards from a hard node in a day is actually better-than-expected.

Anyway, in a truly random system, some toons will end up getting starred up much sooner than others in any case. So the more data you have the more certain you can be.