If you could be so kind, please provide me a list of benefits I would gain with a Property Manager.Again, thank you for your feedback.

You need to do a cost-benefit analysis to determine if it's worth it.  

When it comes to real estate, here's a general list of eligible assets and their depreciable lifespans that you should know: Residential Rental Property = 27.5 yearsThis includes any building or structure where 80% or more of its gross rental income is from residential units.That means:- Apartment buildings- Single-family rental homes- Duplexes, triplexes, and quadplexes- Mobile homes (used for residential rental)- Any kind of residential lodging facility where the primary purpose is long-term rentalCommercial Property = 39 yearsThis includes non-residential properties like:-Office buildings-Retail stores and shopping centers-Warehouses-Industrial complexes-Hotels and motels that do not qualify as residential rental propertyLand Improvements = 15 yearsThese include sidewalks, roads, fencing, some landscaping, and parking lots that are separate from the building.Personal Property = 5 or 7 yearsPersonal property used in a rental activity usually has a 5 or 7-year life.This includes most furniture, appliances, carpeting and various machinery.Qualified Improvement Property (QIP) = 15 yearsGenerally, this includes any improvements made to the interior of a non-residential building after the building was placed in service, excluding elevators, enlargements, and the internal structural framework.Computers and Related Peripheral Equipment = 5 yearsVehicles = 5 yearsNote that the land itself is not depreciable.

And, factor in the depreciation and other tax benefits, deductions, home office, vehicle expenses, etc. 

They are usurping your property for the benefit of the public.

How many years managing is equivalent to the benefit of the 20% down? 

If they are relatively the same but offer a front desk etc maybe they are superior. 

Yes, there are some circumstances that would allow you to assume it; relative, death of a spouse, etc.

What I'm wondering is: is there a way to get the cash invested into this rehab back out of the property in a relatively short timeline, as if it were a BRRRR?

You are (older/retired) and could benefit from house hacking and buying a duplex, or renting a room.