I have found that it is difficult enough to get people to call when they should without charging for 'service calls.'

A difficult, but safe approach is to pay for a 6 or 12 month option to purchase the office building.  

It is difficult to speculate all that you might run into.

But, now laws are much stronger, identity much more difficult to hide.  

where how difficult it would be to get a variance to make the basement a legal rental?  

You would have to convince the county recording offices, who are run by career employees who in some instances still are using fax machines and rotary dial phones. 

Why not do Property Management, I see you already are a licensed RE agent, getting a license through Hotels & Restaurants is not too difficult.

Theyre difficult to deal with at his point; not allowing access for capital repairs.

My own realtor said that 2020 was the most lucrative year of her career and that nearly all the people buying houses in Waco are people who are fleeing California, New York, and Oregon, moving to Texas in hopes of living in a free and functional society again.

Having an expert landlord attorney involved will help you a lot.As for the actual question, it is very difficult if not impossible to "stop" a tenant from damaging your property, because you are not inside the property to know what they are doing.