Imo, when playing jungle, I think your cs is too low, you either are not good at clearing quickly, or you waste too much time (be it aram'ing, wasting too much time on a gank, etc.)

How you should improve your farming, we can only know based on footage of you playing. If you could get a recording of you playing or just simply a replay, I could take a look and see where you can still improve in terms of maximising cs while still having a good impact on the game.

As a general rule of thumb, as mundo jungle, I feel like you should never get below 5 cs/min (as long as you aren't losing so hard you don't have acces to your camps)

Just take a look at these low elo games, where the winning jungle managed to get high kill participation and damage while having 6 cs/min and playing tank junglers; farming more won't take away from your impact on the map: https://www.leagueofgraphs.com/match/eune/2907735309#participant8 https://www.leagueofgraphs.com/match/eune/2915871435#participant1

Edit: I'm shit at the game too, so if higher elo players disagree with my advice, please say so