I did some experiments a long time ago and while I got a Nano 33 BLE to work as peripheral and central, the whole system did not work reliably and I could not get the device to do anything useful on top of the simple experimental code.
Most of the mbed and BLE code is hidden inside a binary library so analysis is difficult. Without using a debugger it is even more difficult. The Arduino Nano 33 BLE has some pads at the bottom to connect a debugger.
Sounds like you might have the skills to figure this out.