Not an electric expert here, but most brushless outrunners are 1500KV and lower, to turn props at a reasonable rpm, for slower/ trainer or scale aircraft.
High KV usually are found on EDF jets and other faster aircraft, such as a flying wings.. gear boxes change things all over again

best to assemble your power system first, battery, ESC and motor and prop, then you will know what aircraft type and size you can power.