M6 Mark ii Focus box size question

I reckon because the M6ii has spot focus and the M50 doesn't, that is why you can't make the single shot focus box frame smaller when in single shot with the M6ii. I've been through the menus many times and there is no adjustment that I can find. (Learn something new everyday!)
Being mostly a full frame shooter, I am surely loving this smaller and lighter M6ii, what a great little camera for good light general photography!