@Audrey Sommer I have been an REI in the Dallas/Ft. Worth area for over a decade. I have been a realtor for +8 years helping out-of-state investors buy and sell here successfully too. The work colleague you mentioned was definitely incorrect.
First, Texas is one of the most landlord friendly states in terms of laws. So regardless of "sentiment" towards out-of-state investors you may have received from your work colleague its incorrect.
Second, Texas also allows Texas homeowners to do cash-out refinance their primary residence. You as a home owner can use the proceeds as you see fit. Also, you can get a HELOC on your primary residence and use the proceeds to purchase investment properties as well. Because I have personally done both and continue to do it to add to my portfolio. But recommended you also reach out a investor friendly lender. I personally use @Andrew Postell. He is my preferred lender, as well as, fellow investor too. So connect with him. You did the right thing coming to BP and posting the question. Better to go right to the source. Andrew will give you some great guidance on investing in Texas regardless of your exit strategy.
Also, no counties in Texas prohibit long term rentals. Some cities you need to register. But your colleague may have been confused about Short Term Rentals (STR). That is a different exit strategy altogether. But would recommend you start with Long Term Rentals first. I will be happy to help you with your search too. My contacts become my clients contacts. Regardless of your exit strategy better to have "Boots on Ground" wherever you invest. hope this helps.