With weed, you run into issues of medical marijuana and people making claims of medical necessity.

Not hacks exactly, yours were great....but I believe that the two most important are 1) Being super clean, you almost can't be clean enough, 2) Be unique.....Set yourself apart from the competition.Beyond that, just be fairly priced (esp on cleaning) and limit the extra charges, I always just pass when the fees start to add up....

A bankruptcy that's not their fault, medical bills, foreclosure all could be reasonable.

You need to create a UNIQUE value proposition, and in the world of STRs, that not only comes from many areas: namely the property's ability to capture attention on the platform and the guest experience from response times to questions or booking confirmations, to comfort of mattress and towels, to enough toilet paper being on site, through to checkout requirements.

Maybe you're just not ready for this type business or could find a way to figure it out on your own.Alternatively, look at medical doctors.

Every submarket/micromarket is so unique, it's hard to know what your's can support when it comes to retail, and what it would be like to deal with those types of tenants, especially small business owners who may operate on a razor thin margin, like most food/coffee businesses do. 

They can provide insights specific to the Dallas market and help you make informed decisions based on your unique situation.

Unless you have large medical bills it's not going to make sense.

But, you need to have a well marketed, unique property.  

But generally speaking, investment properties require a minimum of 15-20% down and sometimes 25% for first time investors or tricky/unique scenarios.