Not every state or city mandates that any landlord has to accept Section 8, because the landlord has to not only subject their property to Section 8 inspections, rules and regulations, they also often have to separately arrange for the tenant to pay the non-covered part of the rent and can face difficulty evicting just based on that.

Narrow down your location based off of your comfortability, budget, local property owner regulations, and rent to price ratio, and you'll be building a portfolio in no time. 

Not following the requirements (within Seattle city limits will likely have additional rules and regulations) opens the seller up to liability.Additionally, the seller always has the option of offering "cash for keys" arrangement but be sure that no funds change hands until after the property is vacated and locks are changed.John

It is the worst because you need to understand the patchwork of regulations across the state, which can vary down to a neighborhood by neighborhood basis.

The final wild card is government regulation and how it could affect the investment.

The regulations around what properties you can add Tiny homes too was cumbersome.  

Ramsha - most of the regulation for a STR is controlled by the neighborhood HOA.

And the numbers are pretty good on the projects I've looked at. these are the very recent regulation that's from what I read, it makes more sense to add ADU into small MF.

I didn't even think to check my local govt on the regulations about rental property.

However, strict IRS regulations apply, including prohibited personal use and mandatory income and expense management through the IRA, with penalties for violations.