How many app downloads per day is good in audience base of 10 M?
I don't know what you are exactly asking. But see what many downloads your competitors are getting. And compare them to yours. Its the best case scenario.
There is no way that anyone can say you that. Even if you get good number of downloads then also remain one factor that is you are unsatisfied with the results.
We have competitors but for our app not so much because its unique in its own way.