So I am looking for information on what to use as the base/patio material. 

The plan: I am identifying on/off market properties that are targets, will do all of the real estate work (listing, showing, advertising, vetting, etc) and will split the cost of the purchase of the home and the material costs for any needed repairs.The contractor will be subbing out portions of the job and be on site mostly full time until the project is completed. 

This tells a familiar story of labor and material shortages.Note: Obviously, a big part of the recent rise is COVID-related.

I'm located in Dallas so the labor cost and materials may be different but you can get an idea at least.

With most furnished properties renting for more than $2,500, MTR seems to be a way to significantly increase cash flow.WeaknessesEnsuring that the property is continuously occupied will largely depend on factors such as the unit, its location, furnishings, and related marketing materials.

Have you ever ordered bulk materials from there?

Many of them will jump into property management, thinking they can retain clients and earn some easy money by collecting rent checks.

My goal is to purchase a small multi-family property with an FHA loan that I can self-manage while retaining my day job as a software engineer.I have been causally reading books, listening to podcasts, and self-educating on personal finance and different asset classes for the last 2 years before finally deciding on real estate; but I still feel like I do not know enough to go at it alone.

Alot depends on material choice and design complexity. 

Pay for labor only per job and cover the material cost yourself.