Really appreciate your thorough feedback and thanks for pointing out areas of improvement!
There's definitely a balance to strike between having agency over the game and actually simulating the market. I made the "support" clicking intentionally weak as it teaches you that you can't run the businesses yourself. Originally wanted to use it to position your investments to avoid bears and hit bulls, but it caps out really fast at 1.2x so it's not good enough for that purpose. In a future update, I will make it so clicking on bears and bulls moves them instead of relying on your support modifier to navigate. I could also have left click actually put more money in the investment for better returns, though that may be reserved for a perk effect.
I agree that having a tab to show your current investments would be super helpful! It might also be worth it to sell them so you can afford something you couldn't before.