I just noticed this same behavior on my Thinkpad L13 Yoga. It correctly hides the checkboxes in normal laptop mode but when I flip the keyboard away in "tablet mode" then it ignores your setting and forces the checkboxes. Ignoring the fact that I flipped it into tablet mode to make room for my much better keyboard and am still using it just the same as a normal laptop. So as seems to be the usual workings of Windows 11, Microsoft knows what you want and if you don't want that, you should change your mind and do as Microsoft has deemed is the correct way of doing things even if it makes no sense.
Please pay attention to all of the feedback that is being provided for Windows 11 asking you to actually give us the options to customize things the way we want them to work instead of forcing things on us.