This might seem ridiculous to some extent, but I have created an app to keep track of my battery cycles of my Mavic Air 2.
I have my 3 batteries labeled with a number (from 1 to 3), and every time I charge one of the batteries completely, I increment the counter in the app, very simple.
And before I fly, I check which battery has the lowest amount of cycles, and I fly that one.
Also, I sometimes check the numbers with the ones in DJI Fly, as sometimes they seem to get off a bit...
The app supports multiple drones, and multiple batteries per drone.
Here are some screenshots:

If for some reason wants the download link (android only), click here to download the APK!
I have my 3 batteries labeled with a number (from 1 to 3), and every time I charge one of the batteries completely, I increment the counter in the app, very simple.
And before I fly, I check which battery has the lowest amount of cycles, and I fly that one.
Also, I sometimes check the numbers with the ones in DJI Fly, as sometimes they seem to get off a bit...
The app supports multiple drones, and multiple batteries per drone.
Here are some screenshots:


If for some reason wants the download link (android only), click here to download the APK!