I live in Khon Kaen. It’s a busy city but not touristy - all Thais (most of the business money is Chinese Thai).
Businesses open and close regularly. Research is critical as you need to tap into demand, actual demand and not family wishful thinking.
Get out and about and talk to the farang in businesses with their Thai partners. Listen to them - not the wishful thinking!
(Saying here is you only spend what you can afford to lose and/or walk away from! And do not spend your retirement money - you need it, not the family!)