The approach of hiding the off-canvas menu using custom CSS is a literal cosmetic change rather than a proper solution. Disabling a feature by simply hiding it doesn't actually turn it off and might cause other issues down the line.
Implementing a proper disable function would be a more robust and scalable solution. It would allow users to switch off the off-canvas menu completely without relying on custom CSS, which can be fragile and harder to maintain.
Would it be possible to add this as a feature request so that when you disable the off-canvas menu, it is actually disabled?