You will have to go to a shop from the SIM card provider, get a letter of certification that this is your number, cost 100 baht and bring that to your bank with passport. I did that just before I left end of April, because I heard in the news about it.Also Bangkok Bank.
I had to bring fotos from me in my room, in front of my rooms door and in front of the house number. They gave me a Line contact and asked me to video call this number once I’m back at the hotel and then show them the above mentioned.
I think it was something around 40.000 for opening a bank account ( had to buy an insurance from the bank which was included in the hole price, retirement visa, visa extension and multiple entry.
You might be able to help yourself. Search Liebscher&Bracht on youtube.They have a English and German channel. Most of the time it’s just some muscle that needs stretching.