Have you tried the USB method? Did it fix your Bluetooth lag? Let me know in the comments below! Disclaimer: Always ensure your vehicle is in a well-ventilated area and your battery is fully charged before performing a software update.
Never interrupt a software update. If the power cuts out or you yank the USB at 80%, you may need to tow the car to a dealer to re-flash the ECU. bmw software update download usb
If you have a 2018–2023 BMW (iDrive 6 or 7), USB is often the only way to get full map updates. For older models, it’s the only way, period. Have you tried the USB method