The Diatone Mamba EASY F722 MK1 Flight Controller features the latest F7 MK1 processing technology, which means you can focus on flying, not on the limits of your equipment. Diatone's Mamba series gives racers an edge in the competition!
www.getfpv.com
^^ should be good and fits in the price range basically any F7 FC has the same processor at the core of it so is just variations on the other components on the board (IMU mainly) and layout of the pins/pads (some have voltage regulators to get output voltage for vtx or cameras or other "peripheral" devices)
Regarding the protocol from the receiver, it is always I think the biggest pain point with setting up betaflight is getting the receiver configuration in there correct and finding the pin to use for receiver input. Basically everything is configurable in betaflight configurator desktop app, so would get that and watch Joshua Bardwell's vids on the latest betaflight or some older ones to get gist of where things are and what you need to configure to get things flying. In general the FC manufacturer will post some "default configuration" you can use and have wiring diagrams to show how to connect things assuming using that default/base configuration but you'll probably want to get into betaflight and tweak/tune some things based on any differences in how your quad flies (depends on frame and power to weight ratio at different RPM and other things, ecalc.ch good site to punch in numbers and get some idea of power consumption and power to weight but is always some guesswork and tuning things by "feel" and/or blackbox logs).
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Regarding the receiver too just need to know the output protocol and that the receiver input on the FC will support it, generally the F7 pins can be reconfigured as inputs/outputs and have various internal timers in the chip tied to different pins (it's very flexible I hear in this regard compared to predecessor F4 or F3 chips, but still would check docs between receiver output and FC input to see if things seem to line up)