How do you learn to be comfortable being nude around others outside of your private 'safe space' home environment?

I've never been nude in public and even in high school I used to be very careful not let other people see me nude when in the sports changing areas or in swimming pool changerooms. Yes those spaces were just other guys but that doesn't matter.

Dad bod isn't attractive to anyone (esp women) apparently.

I think I'd even had trouble with nudity if I was ever to start trying dating again and the prospect of adult intimacy approached.