@Zeb Duncan couldn't agree more with @Brenden Mitchum that at the end of the day you have to just pick one. In addition to what was mentioned, you can quickly hone in on a few states if you start looking at things like the Sunbelt states (where the population is expected to grow the fastest over the next 30 years), landlord-friendly states, places people want to live now that they have an option with remote work (think mountains, lakes, oceans, etc.). I could make a case for a dozen different secondary markets with good cash flow and a high likelihood of appreciation. For me, that included places like Little Rock, Fayetteville, Huntsville, and Cape Coral.
In addition to doing your own market research, feel free to shamelessly leverage the research of others. For example, talk to some turnkey companies like Rent to Retirement who are in many markets and see what they think of different markets. Look at real estate crowdfunding sites like Fundrise and see where they invest and why.
Even after you have a market nailed down, your work is honestly just starting. It's much easier to tap into an experienced team with a turnkey provider at first and then branch out from there. Building your own team can be done, but be honest with yourself about your bandwidth. I think many people on BP celebrate the DIY model out of state, but gloss over the hundreds of hours spent finding and managing that team. Happy to chat more if it would help.