If so what pads on the speedybee f4 v3 would it connect too?
any of the serial ports can be used you just need a 5V pad, TX RX and GROUND, then set the port to mavlink2.
I think SERIAL3 -> UART3 (User defined) is avaliable for Sik telemetry(GND/5V are really close).
Most other UART has their functions, but you have to check your configuration. If those UART are available then you can use at your choise.
https://ardupilot.org/copter/docs/common-speedybeef4-v3.html