Interestingly enough, I've reached my wits end with paruresis (shy bladder) and have stopped trying to pee in occupied public washrooms entirely. It's pointless. I won't be able to go. But I did find that if I just go to the stall and pretend I'm taking a shit, the pee flows like wine. Doesn't matter if there's one or several people in there. The real struggle is when the bathroom is initially empty, so I think I'll use the urinal after all. You bet your ass thirty guys walk in before I can start.
I have a real admiration for dudes who just piss, shit and fart freely in a public space. It must be positively liberating. Like a pack of ancient kings, burping and laughing and feasting on chicken.
Oh man I understand your pain brother. Have the same issue but I got "lucky" and was forced out of it. Was in a situation where I had to piss/shit in a public bathroom for 4+ years. Still happens sometimes when I'm in unfamiliar places and there's more than 1 other person in there. Don't know what it is about the anxiety man. Just feels impossible sometimes.
Just last week I was pooping and when I was done I noticed that I didn't pee. It was weird. So somehow it is possible but I don't know how I did it. The mysteries of the human body.