$24,000, or however much you have available outside your other investments, isn't really very much to start with, definitely no where near enough to generate $4-5,000 of profit a month. If by commercial real estate you mean purchasing rental properties, you could probably find a property being sold by the owner, or another investor, and work out a seller financing deal with them where you put 20% down, and make payments each month. You'd really only have enough money to purchase a $50,000-100,000 property, which would eat up your entire $20,000 and you'd probably need more to make any repairs.
You could also use the money you have already to flip a home, using a hard money lender. They usually want you to have skin in the game, so probably 20% down again, but at least with flipping you'll get the money back, plus your profits, within 3-4 months (If everything works out of course).
You could also look into wholesaling, but that's a lot more hands on in the sense you have to really put a lot of time into searching for deals, and networking with people. It might be a bit much for you if you'll be working full time as well.
Overall, for the amount of money you have, and your goal, I'd personally recommend looking into flipping, until you can save up more capital.