Ask HN: What would you do if you suspect a competitor is 1 star rating your app?

I have an app that gets about 400 installs a day has about 500 ratings and was rated 4.8-4.9 on Google play. Across the 500 ratings it had 2 legitimate 1 star ratings with reviews. The app has climbed the Google Play search results and was sitting at #3 for a very competitive term. About 3 days ago we started getting what we think must about six 1 star ratings a day without reviews. Google Play Data is delayed by a number of days so it is hard to be sure the exact number. But now 3% of the overall ratings are 1 star. The app hasn't changed. No problematic crashes. No server issues. No support tickets complaining. We suspect it is a competitor that is 1 star rating our app.

Naturally we've reached out to Google via Google Play Console. But I doubt they will take notice.

What actions would you take?