I’m always surprised at the number of people complaining about the Venture. It is a superb little ship. 5K M3 capacity with frigate cost and speed. Decent yield with 2 bonused lasers. What’s not to like!
The problem people are experiencing is that the ship is too good and an oversupply of ore is depressing the price. Mining more won’t fix that - you need to mine strategically.
The best ISK/hour with a Venture will be gas mining but, if you want the safety of highsec - mine ore that is rich in Mexallon (Plagioclase, Kernite, or Jaspet which can be found in ore anomalies). Compress the ore and sell it in Jita.