This appears to be a part number specific to the programming of the CPU/DSP based on a generic part. For example, here is a datasheet for the Zh-Jieli JL AC6905A that has a BT 4.2 radio. So these cheap little BT 4.2 gadgets from 2017 onward may have this generic device.
It may be that buyers order a specific programming and the actual number JL stamps on the device may be tagged to the buyer. It seems that even specs for a generic device can't be found on their site and I don't know why.
It's possible this PDF might be the one for yours, try following some of the signal paths and see if they agree with the pinout.
So I believe what you'd need to do is find another board with a chip that has the same number and lift it, because it seems you can't order one from anywhere.
The generic device for BT 5.0 version such as in the fosiaudio amplifiers (eg ZK-502T line) may have very similar specs to this one, other than improved bitrate and XMT power.