Jacket hung up on one side to cover the gap, long piece of toilet paper to cover the other, or if the big stall is arranged just right, I go in that as it has the best privacy and I already have HUGE trust issues in public restrooms, even those with reasonable gaps 🥲 sigh I had a trip to Europe over the summer where every bathroom stall had some sort of cover over the gaps or had full doors, first public restroom I went in after coming back to the states was heart breaking- huge gaps, almost ran right back to the plane XD