So I was trying to program my flight controller in betaflight today and when I was trying to change the Receiver (in configuration) to PWM, I would hit save and reboot but when it rebooted it changed back to PPM. Does anyone know how to solve this?
You have to go to the ports tab and enable the port you connected your receiver to. Save that page THEN you can go to the configuration page and set the type of receiver. if you set the port and leave without saving it defaults back to last setting.
I would try flashing an older version of Betaflight, as the latest versions that supported F3 boards at all had to sacrifice functionality to get them to fit. I imagine PWM support was dropped for this reason, as it's pretty uncommon these days. 3.5.7 or whatever the latest 3.5 was should work fine.