Hi there. Open the Portal and view the Tharsis Outpost map, then press left on your d-pad to view Renegade currencies you've collected. Turning in dark matter ingots to syndicates will increase your rank while giving rewards in exchange. Once you've unlocked everything at a syndicate, they serve no other purpose than for exchanging for more rewards at those vendors. You can keep depositing for chances at T5 shiny weapons and different rolls.