you're talking about two different things here. The 220 baht is the ATM withdrawal fees for using the ATM of a bank you don't have an account with. Every ATM here in thailand charges that. That is refunded to me. My bank eats that cost for me. The other fee that you keep talking about is a currency converter fee. You shouldn't be selecting that when you withdrawal money from the ATM it cost extra money. I don't know how to say this any other way. ATM fees don't apply to me. Your reasons are not the same as everyone else. My reason for getting a thai bank account was so I didn't have to take 15 to 20,000 baht in cash with me everytime I go outside. It's safer and I only have to bring my phone and like 5,000 baht which is was safer.
Honestly it's just the QR code thing. Like paying your internet and electric bills just by scanning it. I also pay my rent with a qr code. No need to carry large amounts of cash around when you go to the club or anything like that. I just need my phone.
If you're already in thailand and on another visa it's going to be complicated. Get yourself an agent. I used this one while I was staying in thailand. She's very good. Add her on line app