AirDNA is certainly the most comprehensive data source to see aggregated occupancy, nightly rates, and revenue estimates.However, keep in mind that AirDNA is using historical data (from the past 1-2 years) and those years were anomolies due to the pandemic.

So if I analyze potential deals and the numbers work, and I know that the market historically tends upward, then I am of the opinion that it makes sense to invest - especially if you're just trying to get started. 

There are markets that historically appreciate more than others, but because of this the cashflow is generally less. 

It also gives me peace of mind that historically Austin market does very well even in difficult times.

Looking at the historical data for appreciation in a neighborhood could give you a really good idea on what the appreciation rate will be.  

on September 16 Governor Newsome Signed into law SB9 that does allow California homeowners to build additional housing units Subdivide and even sell Smaller lots with additional housing units separately. a Homeowner must be living in the property for 3 years and must have the larger lot size. it excludes Historical Designated homes and districts.

But looking at historical prices, suggested a market difference between the Subject neighborhood and the more expensive one.

Do you have motion sensing lights set-up in your historically troubled areas of the property?

Alternatively a personal loan to buy the building and then I can fix it up down the road since it is a historical building and I might need time for all that process and getting the tax credits, I have 50% down payment and excellent credit, Other option is to get some type of portfolio on loan based on my other investment properties?

Sure you may have a few one off names, but the overwhelming historical fact is that detroit was a manufacturing hub, and those all shipped over seas, or out of state due to not having their personal favors and tax sanctuaries put in place.Also, hows the police force in detroit?