You have to think differently. The Aiyima can do aptx HD. The bottleneck is your smartphone. There is always a transmitter and receiver.
Bluetooth A2DP codec comparison of Xiaomi Mi 11 and Xiaomi Redmi 9
bluetoothcheck.com
Maybe a costum rom or the developer mode on your smartphone will help.
Thanks!
But, that's not the case for me.
On my smartphone Redmi 9 is the official, European firmware android 11 and it supports all bluetooth codecs.
On my smartphone, by default, the selection of the codec is automatic.
The best available codec is turned on, which is supported by the receiving module.
It is possible to select a codec in manual mode, but this is not convenient.
There are seven codecs available in total.
I have three devices with bluetooth.
D03 - SBC.
Topping dx3 pro+ - LDAC.
LOXJIE A30 - AAC.