Very late to the party here but I'm on MIUI 12.0..0 on a Huawei P30 Pro
At first, I was unable to get data through too, tried alsorts of tips from here and elsewhere.
I managed to get data on my AA but not on apps on my phone by using the fake proxy.
I could get it on both using Speedify VPN but that's not ideal although not a bad option.
Then I noticed when i deleted everything adn started again, it worked for the first connection. Saying "Automatically connected via Google Play services (good quality)" on my wifi settings.
I lost connection after that, when I connected for the 2nd time.
I messed around a bit more with various hints, deleted and reinstalled. No idea at all what I have done but for the past week it has connected every single time using Google Play Services and data has been flowing everywhere!
I don't know how I did it ,I haven't rebooted my phone since (I daren't!). Just wondered if that hint might help someone who knows better how to force it to go through Google Play Services every time or help with another workaround.