When DD outgrew the strollers at Disney 30+ years ago when she was 4 because of her leg length, we opted to rent her a wheelchair. Might be an option to consider.
Years ago, we had a sit and stand that had no shade for the kid in back. I took a shade you buy for a beach chair and managed to attach to stroller. In truth, I probably spent more time figuring how to do it, than the kid used it. Lol
I have some pictures. He was being silly, so they aren't the best pictures, but you can get a sense of him inside the stroller. I also included one of him standing, so you can get an idea of his body type. There is plenty of headroom with the canopy down.