I am trying to fetch the BR/EDR bluetooth paired devices list from my app designed for iPhone, but CoreBluetooth only supports Bluetooth Low Energy. Could you please let me know whether there is any API to access the Legacy-Bluetooth feature using Swift/Obejective-C for iPhone.
iOS 13 / 13.1 introduces support for GATT via BR/EDR and adds a new API to Core Bluetooth where you can register for connection / disconnection events of Classic devices, based on the GATT service UUIDs (see WWDC 2019 Session #901 - "What's New in Core Bluetooth")
So if the Classic device supports GATT via BR/EDR and the services have been discovered upfront, then yes, you can query these devices without the need to do a BLE scan. Essentially, this is a subset of the paired devices. Not sure if this is what you need.
If not, you'll need the External Accessory framework and MFi support on the Bluetooth accessory.