Am I missing something? There's no arbitrage trading opportunities as far as I can tell so what cargo are you supposed to be hauling? Piles of looted succulents and notepads?
(Serious question! I like space trading games but I don't see that as a thing and I really am curious if I'm missing something.)
Just hold the 5000 argon in your inventory. I think I was walking around at 70,000/185 for a while...
Just have to load it all into the ship, talk to the person and rinse repeat that small loop
That's what I've been doing.
But dropping the argon inside your ship might also count as cargo. Decor items like weight-plates, dumbbell etc uses up cargo space. Will try it once my Aluminum storage is full again.