I am new to Quantconnect and have a few questions:

1. What does unrealized, fees, and net profit mean in this context of the backtest?

2. Which brokerage is preferable for the buying/selling of a large volume of shares?

3. If I want to make a high volume of live trades by myself, should I go prime or professional?

4. Have people been profitable with Quantconnect and seen success?

Any feedback would be helpful, Thanks