The OP is avoiding having us hear a bit of the actual vocalists he wants advice on recording. So we can all imagine or extrapolate helpful recording advice based only on his writing and on clips of other vocalists using other microphones in unknown spaces. I am not faulting the OP’s intentions or accusing him of anything sneaky, I am trying to point out that specific real examples can result in specific comments and help. There are many good general tips in this thread, but none of them are specific to the OP’s rappers, mics , room or whatever else we might hear in some examples. Does he have a clip or short example of his specific situation?