This is a video on how we convert an Arduino to operating voltage from 5v to 3.3v. This is a modification that requires soldering.
Link where you can buy parts:
Arduino - https://amzn.to/38xuKRJ
3.3V Regulator - https://amzn.to/3gAmymu
Logic Level Shifter - https://amzn.to/3gAmd3c
With modified 3.3v arduino, it can now be interfaced to a 3.3v sensors and devices without the need of logic level converter shifter.
The regulator must be changed, the fused must be removed and USB 5v must go to the Vin of the 3.3v regulator.
Please be warned that the Arduino is overclocked when we run at 3.3v the Arduino UNO's atmega328 at 16mhz clock.