I currently have 4 SFH rentals in the southeast, 3 of which are owned free-and-clear save for property taxes and insurance. 

That being said, there are also more financial risks and permitting is notoriously tricky.

A tenant who pays late every month eventually doesn't pay then lives in your rental for a few months free.

That increases the risk of fire.I've given her notice that we will not renew her lease.

Doing some risk analysis.Let’s say I buy a property now and market value drops soon by 20% is it better to have less downpayment such as 20%.  

Hi, yes great choice Ohio is a great place to invest in if you have any questions feel free to reach out!

Feel free to drop me a message, always happy to make connections and learn from others. 

I'll be honest the new building/development world is extremely tough to get into and unless you are planning to do it at scale or have a super unique way to find land/deals the risk usually isn't worth the reward. 

@Brent BagenStessa is also a good option that is free with BP Pro. 

It's part of the free economy and capitalism.