smart visa holders hv troubles in opening bank accounts as well in many branches. BOI got to issue an additional letter to confirm their right. For LTR, it’s still required to get work permit. For DTV I don’t know yet if it’s convenient to get wp because most officers at employment offices don’t know about it yet. Anyway it’s worth a try cuz it’s a convenient way to obtain a bank account.
You can leave within 31 Mar 23. Work permit cancellation is employer’s responsibility. The employer can be fined from not doing it. Many of my colleagues left the country like this and they came back again with new non-b from a thai embassy abroad. No problem at all.