Betaflight servo setup sucks!

Finally got an old betaflight board to work with a 3 motor+2 servo foam wing. I'm was looking for the ability to have differential thrust but with a 3rd motor for straight throttle. After hours of trying to decipher the mmix and smix setup in betaflight, and getting desync issues using motor outputs, i gave up and just went old school pwm to the 3 motor and set beta fight up for use with "5 servos".
Digital servos can handle over 200hz so setting servo pwm to 250, i was able to run the 3 motor just off those outputs. Betaflight doesn't even see any motors . In this way i was also able to get self centering on my differential thrust, before with it being motor output, i was unable to find how to get betaflight to center those channels without manually moving the sticks (acro mode kinda deal, motors just stay where you left them)