Is it true gym is really bad for singers? Everywhere i look they say swimming is top tier for singing

Lifting heavy weights to build a bigger physique.. I never see buff singers so maybe theres a reason?

Swimming and other forms of cardio are great for increasing your lung capacity, which helps singers! Plenty of pop stars spend a lot of time in the gym, as they're dancing at the same time and keeping up celebrity appearances - and it doesn't seem (at least anecdotally) that their vocals suffer.