
Start at a bathroom you know not to be too busy, ones in the basement or out of the way. Once you do start to use more populated ones, just keep your eyes to yourself. Walk straight to where you're going, and then back out again. As long as you act like you know what you're doing, nobody will say a thing
Second this. Act like you belong there, and you’ll look like you belong there. Also just cuz I know this was an odd source of anxiety for me: people are not going to notice (or care) that you’re peeing in a stall instead of at a urinal. Do keep in mind that most men’s rooms only have 1-2 stalls, so you might need to look in a few different bathrooms before you can find an empty stall. It’s not weird to wait for one so long as you aren’t staring at people lol
Oh I absolutely get that, it feels like everyone is perceiving you all at once while you’re just trying to pee. But honestly it helps a lot to just remember that everyone else is also just in there trying to do their business and get out, they don’t really care what’s going on around them so long as they aren’t being watched or bothered.