Have you received Android 9.0 builds of MIUI 11 on your Mi Max 3? Fear not, as Android 10 versions are incoming. You can already download an Android 10 build of MIUI 11 for the device too, although there are some caveats.
https://www.notebookcheck.net/Xiaomi-Mi-Max-3-picks-up-an-encouraging-MIUI-11-update.447129.0.html
If you go to Xiaom.eu you can download the same version with Google play already installed and all working well,very good rom