Uart voltage warning and STM32 FC

Hi there,
I’m putting together a openHD system using a Pi0 as the air unit and a pi4 as a ground unit and I’m currently running the AR9271 blue wifi adapters. I am about to connect up the telemetry and I’m just posting to make sure I’m not missing anything, I assume the warning in the WIKI about 5V UARTS is for older FC running AVR microcontrollers and not the current batch running STM32 microcontrollers. I currently have a MAYTEK F722 and Omnibus F4 FC and from the datasheets for both microcontrollers, it looks like their UARTS are 3.3v so I should be right to connect them straight the the Pi0 UART. I have already killed a Pi0 and a Pi3b+ with stupid mistakes and I’m not in the mood to make anymore so if I have overlooked something could you please let me know.