What are realistic ROI expectations in the Chicago area (multifamily)?

[Jason F.]

Medium income healthcare family.

Family W2 yearly salary: $175k. In two years: $300k. In seven years: $550-600k.

Net worth right now: $700k.

Previously owned small rental units and flipped a few homes. Liquidated nearly everything to build our primary home which is under construction (this is where our net worth is all vested.) I will have no student loans or mortgage, car payments, etc. Everything is paid for within two years.

When money starts cranking in, well, we are used to living lean. I think our family of seven spends about 60k a year on bills, food, etc. and that's it. We have no other bills. I don't want my kids to realize we will be wealthy.

If I dump EVERYTHING ELSE that comes in the next 20 years into Chicago 20+ unit multifamily properties what kind of return on investment would I be looking at long term? I'd be putting down 20-30% on each property. Assuming I hire a reputable company to manage the properties. I don't even know where to begin calculating that. I know that if we both just keep working as nurses and finish becoming CRNA's with the higher income potential and regular raises we would be pulling in around 10 million gross in twenty years.