during the "boom" times but COVID has loosened everything up and now 5% can be had in Manhattan, 6%-7% in Brooklyn and even 8% in the Bronx.

Manhattan is super high density. 

That said, needing to commute to Manhattan daily meant high rent & small apartments, but COVID & WFH may have changed that calculation.

I own properties in Gatlinburg, PF, Sevierville, Douglas Lake, and Cosby.  

I know in places in South Florida and in Manhattan, you might.I doubt you need one, though. 

I am located in Manhattan, KS.

But, some of the rental property complexes in the PF/S'ville/DWood area are extremely steeply graded and some 2WD vehicles might be able to get in when it's dry, but not out with ice/snow.  

Flipping in Manhattan is ideal if you can find the right property.

I wouldn't compare the 2 property types using the same metrics - especially given the unique market conditions in New York City at the moment.That being said, I'd recommend the house-hack route in which you specifically target 3-4 unit properties. 2-unit properties are also good targets b/c there is more inventory than 3-4 unit properties & some 2-units have ADUs.Depending on which outer borough(s) you're targeting, we can discuss which specific areas would be the best fit for what you're looking for - Overall you'll find higher cap rates & IRR the further North and  Southeast you go from Manhattan/NYC (i.e.

Manhattan, Los Angeles, Chicago, Philadelphia) should get low-digit area codes that were faster to dial, 212, 213, 312, 215.