Second button down on the right side of screen (almost always).

I read once that it’s an accessibility requirement that the screens can be muted.

I haven’t encountered a screen that I couldn’t mute in the last 10+ years.

FWIW, third down on the left is what works at a local chain.

(I was gonna say something about “brute-forcing” it but I know how that might be misinterpreted. Just try all the buttons, if necessary.)

The only constant is this: It varies.

I start with the buttons on the right, because I am right handed and that's easier for me. I start with the top button and work to the bottom.

If silence has not yet been achieved, then I do the same with the buttons on the left.

If silence has still not yet been achieved, then I make a mental note to never give that location any money ever again. (It's a short list, and the irritation makes it very easy to remember each location whether I want to or not.)

(I don't worry about how "brute forcing" might be interpreted. I am doing nothing wrong.)