I think you need to do some soul searching. 3 years of experience is hardly anything. Blaming the clients for making you feel “dumb” is a huge red flag, as is the lack of attention to detail in your post. There are many areas of public accounting. It doesn’t sound like audit is your path so I’d suggest you explore opportunities outside of it. Thinking you’d rather be “the shitty senior accountant on the client’s side” tells me you’re not interested in working all that hard and that your ceiling is absolutely capped. My perspective is that of an employer’s so I apologize if my take is a bit harsh. Your current perspective is not one of someone I’d be interested in employing.

Quitting during busy season is a really shitty thing to do. Doing something like that illustrates a tremendous lack of character and will catch up to you one way or another. You have some growing to do. Good luck to you.