With your ATM debit card, you can withdraw up to 50'000 THB a day in any ATM aoutside Thailand that carries the symbol Union Pay. Only 100 THB fees per withdrawal.
Indeed, without a work permit, one cannot have e-banking on a PC. However, if you have a Thai phone number, you register the numbre at your BKB branch, dowload the BKB Apps and you can access your account via the Apps. In the meantime, you can transfer monney from anywhere in the world via the SWIFT into your BKB account.