My main bank account was with Bangkok Bank and there were regular banking issues, ie taking money out of my account against my wishes from two companies in Cyprus whom I have never even heard of, I lost about 2000Bt.
I only kept my account with them because I make regular transactions with Wise. About a year ago I got an account with Krungthai bank and put the majority of my money it to it, and it has been very satisfactory.
The very fact that nearly every time I go into my Krungthai bank it is busy. Contrast that with my nearest Bangkok Bank branch which is always nearly empty any time I went there, surely that tells you something.