opening a bank account is not easy. Best pay an agent.
Guessing you have 100-200k in savings. It's really easy to go through savings and not easy to find work. Alot of people are working illegally, either ok the islands or in the north of Thailand. You could work as a digital nomad and there is a visa for that. You cd set up a business here with a Thai partner perhaps, but huge risks. Or do what most of us do, get married with a Thai and that opens up doors (as well as huge risks)