I'm left with $580 to do what I please, right?
Nope.
That unit will be vacant some of the time. You will still have to pay the mortgage and other bills.
So, if you think it will be vacant 5% of the time, you need to set aside 5% of the gross rent to cover that in the future.
Each and every day there are multiple items wearing out a little bit more. Eventually they will break and have to be replaced or repaired. You will need to set aside money that will be used for a new roof, new paint, termite treatments, new water heater, new hvac system, etc., etc. Depending on the age of the house and the key items in it, that might range from 10% to 20%.
And you will need to ability to pay for a $5000 roof or hvac system BEFORE you actually set aside enough to cover it because Murphy loves landlords without a repair stash.