However my market is currently Arizona.

Nashville is a ridiculously competitive market.

Since it is a family member and I would potentially buy the property for under market value.

This is one of the main inherent risks with pre-construction, and the pre-construction market has cooled, and with impeding tariffs, there is some uncertainty around where prices will be in the coming months.One thing to clarify, are you looking to buy an investment property or a primary residence (or perhaps abit of both where you live in one unit and rent out the other)?

This year I may see if if I can get a construction loan to build 20-30 apartments, then refinance with an asset based lender. what markets?

You may qualify based on Market Rents or Lease Agreement.

They would likely be able to confirm that your expenses are reasonable for the area or that your rents are at market rates.

I joined various internet marketing programs and mentorships to find ways to transition from my W2 job.

My first duplex was a turnkey, off market property.

I don't know how much you have but a build to rent triplex all in our market is 150k liquid normally with full return of capital in 9 months.