Which library to work with Android \ BLE to choose?

Question

Android

I am developing an application that should work with Bluetooth devices in the background, BLE support is fundamentally important. I read the documentation for a couple of days, and came to the conclusion that the rxAndroidBle libraries and a set of libraries from Nordic Semiconductor ideally fit my needs. I felt rxAndroidBle and ran into a bunch of ambiguous things on individual implementations, in my opinion - damp. At the same time, Nordic Semiconductor's NRf Connect fully satisfies all my needs, except that, unfortunately, the project documentation is very sparse.
Can you recommend a library for Android\BLE that takes over the organization of interaction with devices with already implemented components for organizing request/response processing and supporting the Request Response pattern of communication with the device? You don't need much - there is a background service that receives and returns the results of working with a ble device via EventBus. The very work with devices is simple - a subscription to one characteristic, a record there. For some devices, before work, it is necessary to send a set of commands and wait for the CPU to initialize. I would like a solution from the category of throwing a lambda manager or instances of anonymous classes on onSuccess and onFail of the desired operation, where the received data and client/device/connection states are processed. I liked Nordic, but the documentation is very stingy,