Changing when hamburger menu gets activated

The website is set for the hamburger menu to work for screens 920px or smaller. Any idea how to change the px for up to which screensize the mobile menu is shown? ( I already tried with css, but that doesn’t work, maybe js or some setting on backend I can’t find and looked a few times.)
Thanks in advance.

Can you adjust in the theme settings? or customizer?

thanks - I looked there, didn’t see that option