There are two restroom cases:
1. fake men using men’s restrooms
2. fake women using women’s restrooms
As for 1, the fake man would probably use a sit-down stall. If using the urinal, if no man is near, no problem. If a man is near, the real man generally will not care if the fake man (modified women) urinates into an adjacent urinal.
As for 2, the applicable case in case of the Delaware Congressperson, women’s restrooms only use sit-down stalls.
The real problems of gender privacy arise in changing rooms, locker rooms and showers, not bathrooms.
With respect, your analysis is naive, I feel. These demented people WANT to cause trouble. There are plenty of ways to cause trouble in a bathroom.
The males, the pretend trans, mostly do this because it gives them pleasure and wood. Autogynephilia is a thing. Seriously, people with these problems need to be locked away from society. Mental institutions need a comeback.