Your Mdrummer must either be on an instrument track (with midi on the same track) or loaded in the instrument rack (which needs to be triggered from a midi track). A midi track can’t load an instrument.
Either way you should be able to EQ the instrument output channels.
Check you are adjusting the correct channel (look for movement in the meters), make sure the EQ is active and if it still doesn’t work describe how you are loading it on to the track.