No ratings after 30k downloads
I see three reviews only for your app. One on the current version and two on "all versions" and I'm browsing on the US store.

Sadly, I think this is in the normal range (if a bit less reviews) - but you are operating in the free app space with a dollar "remove the ads" IAP.

Apple does not incentivize people to leave reviews - you don't get better genius results, better recommendations - so people don't invest time in a review unless they are a) angry b) pay a lot for the app and it really saves them time or effort.

I would be curious on your engagement rate for the 30k downloads. If you have a solid core of people that continue to use the app weekly and daily - you might over time get a few that leave reviews.