Sorry, I never tried this one at home? Can you move the slide reward at all? If so, gut the top end starting with the slide cover plate, firing pin, spring loaded bearing. This will make it easier to push forward when you pull down on the slide stop lever.
If this don’t help I will try to duplicate the problem and let you know the procedure. Unfortunately I am attending the SAR show in Phoenix this week and will not return until the following Thursday Dec 9th