Many thanks for your highlights.
Yes fully agreed that unfortunatly cheap NANO or PRO MINI does not have state of the art PCB design rules with ground planes.
Supply of NRF24 is requiring also a lot of attention in power rails that shall be as much as possible decoupled from the digital supply of the Arduino, better to have an external low drop out voltage regulator as you mentionned earlier.
For the 3.3V regulation and voltage drop, I do not follow you, to me we have 3.3V output regulation + 1,2V regulation margin which remains well under the 5V input of the regulator ( doesn't includes the 0,44v drop )
The Voltage drop accross the 2,2 ohm shunt is on the ground path of the 3,3V regulator so the NRF24 is seing only 3,3V - 0,44V on worse case TX condition and considering rdson is neglectable against the shunt.
From the NRF24, Radio can even operate with down to 1,9V supply, surprisingly very tolerant.
In my circuit I placed a jumper for shorting the shunt and fullfill a 3.3V supply.
After some trials today up to 154mA , I can confirm the voltage drop has absolutly no effect to radio TX/RX quality, so my jumper is useless, but I always prefer to put it in place for all expect power and sleep measurement.
Again great job you all did.
Just a question related to Statistics, What is the FAIL and NACK % corresponding to ?
It never exceeds few % even so the transmission is continiously failing.