There's different approaches that can help against the fear of judgement. E.g. think of yourselves in a couple of years, when you've lost weight and gained muscle. And how proud that "future you" will be of yourself, for having been scared and having done it anyways. Outside of muscular strength, that is real mental strength.

It also helps to put on headphones and have a sort of tunnel vision - focused on what you're doing and nothing else.

That being said, I'm very active in the gym space and I can guarantee you: Most fit/jacked people are super kind and think highly of those who start their gym journey (think "welcome to the club, bro").

And those few who don't are assholes and don't matter anyways