I am in exactly the same situation. Krung Thai internet banking was just as you say, simple and efficient. The new app is a disaster if you read the reviews. Facial recognition and only via data, no wi-fi connection allowed. I was also going to go to Kasikorn in the next few days. It was either Kasikorn, SCB or Bangkok Bank. Interested to know how you get on. I'll update this in a couple of days if I can open a new account with internet banking. I also have a Government Savings Bank account but you have to be a Thai Citizen to have internet banking.