this post just to tell that the XIAOMI REDMI NOTE 9 PRO run the ZWIFT APP very very well, and that it also support ANT+ connections.
My setup is:
Smartphone XIAOMI REDMI NOTE 9 PRO
Trainer ELITE RAMPA controlled trainer
HRM Garmin dual
If you want to know if your smartphone natively support ANT+ then install the following app: ANT Tester. Once opened , it wil ltell you if your smartphone is ANT+ cabale or not, and in case which are the missing software layer to install.