Thanks for your reply. In the reference about ASHA, there is the following:
It is strongly recommended that the central and peripheral support 2MB PHY as specified in the BT 5.0 specification. The central shall support audio links of at least 64 kbit/s on both 1M and 2M PHYs. The BLE long range PHY shall not be used.
Is that the bandwidth you are looking for?
Using the right (or left. as configured) is only because HFP and A2DP by definition do not support multiple connections. However, BTC is not used for TV streaming, MFi or ASHA. With my Opns, MFi works with either one or both HAs. Similarly the ConnectClip. Similarly the TV box. So in all cases, presumably specialized BLE / GATT profiles must be being used.
Regarding one to many, according to GATT | Introduction to Bluetooth Low Energy | Adafruit Learning System, one central device may be connected to multiple peripheral devices.