Thanks. I noticed that ‘Discussion’ is also missing from your screen options. Is this because of the Disable Comments plugin?
Could you please temporarily disable all active plugins (except WooCommerce) and see if the Sidebar Layout option is there.
If it is, then reactivate the plugins one-by-one, checking each time that you can still see the Sidebar Layout option. If and when the problem reappears, this will tell us which plugin, if any, is causing the conflict.