Yes, the device supports Bluetooth Low Energy (LE). Bluetooth 5.0 or 5.2 with LE is intended for energy-efficient connections such as to headphones or sensors.
The mobile runs Android 15 (Go Edition).
There is no official information from Xiaomi on the update duration. Budget devices often receive 1-2 years of security updates, but exact details are not known. For precise information, I recommend consulting the official Xiaomi support page or asking the dealer.