I am trying to use the RP2040 for some real time applications, and I am running into an issue with reading the A6 pin. It is taking 18ms (far too long for my application) to read the A6 pin when the device is in 'BLE' mode (when BLE.begin() is ran). When I remove the call to BLE.begin() the read time returns to normal. Unfortunately I need the device to be used in 'BLE' mode and I need all of the analog pins. Is there a software fix for this issue? Should I seek different hardware?
The RP2040 does not have a lot of analog pins. Therefore the Arduino team made use of the NINA module analog pins. I suspect the pins you have issues with are on the module and you need to get trough an additional interface (hidden from the average user) to make use of the pins therefore the delay.
I recommend you look at the Arduino Nano 33 IoT and Arduino Nano 33 BLE.
They are different from each other. Have a look at their specifications and see what fits your application better. They both make use of their own ADC with enough inputs.