test apk on multiple devices at the same time

I want to test an android app, on multiple emulators of android devices (but exactly the same model) in parallel. After I login to the app, it takes a LOT of data from a server.

So I would like to test 30 devices, accessing the application and downloading that data at the same time.

What could I use for this? I am a beginner in this, I wanted to try Jmeter, but I can't use it since I have to login on an app, on the device, and from what I understood Jmeter only sends requests to the server. I would like to monitor, what happens when 30 devices access the server, and the server sends back that data I was writing about several lines higher.

Thank you.