Building a small app using CompanionDeviceManager following the documentation from https://developer.android.com/guide/topics/connectivity/companion-device-pairing .
Calling CompanionDeviceManager.associate(...) with an BluetoothDeviceFilter Filter by battery service .addServiceUuid(ParcelUuid(UUID.fromString("0000180F-0000-1000-8000-00805f9b34fb")), null) no device is shown at all despite there is a least one nearby.
My test device is an Sony Xperia XZ2 Compact (H8324, Android 10, Build 52.1.A.3.49).
Calling CompanionDeviceManager.associate(...) with an empty (without any UUID set) BluetoothDeviceFilter i see all the devices around.