However, if it's a property that isn't highly specific to any particular use, and the structure can ideally become an empty shell, these can easily be converted for retail, medical/dental, professional office, learning center/daycare, and the like.

Often they're more educators than practitioners.   

Scratch and dent all the way.

I’m an IRS EA/Tax Practitioner and also invest in Airbnb/Short-term rentals.

My active income is as a mulitlocation/multidoctor/multispecialty dental practice owner, so I really don't have a lot of 'free' time and I worry about the time committment for BRRRR even though the same 200k could go much farther in the long run. 

I stopped at Walgreens to pick up some dental floss and got in line.

You're correct that purchasing properties, renting them out with a cash flow, and repeating the process by adding properties IS, by definition what most REI practitioners are doing.

My FT job is a nurse practitioner.

(Current physician tenants are your best source for finding new tenants, through their professional/personal connections.)Are you looking for solo practitioners, or small groups of 3 to 4 physicians?

@Mike CelliYes many solo practitioners own stand alone buildings.