Southern Baptists do not believe that
I’ve been one since 1965
Very few Campbellite Church of Christ do that anymore either but I too have heard some say that when I was young
However plenty Catholics here on FR think anyone not Catholic is outside of salvation
I am SB, too. I know we do not believe that but the CoC does. The sister of a friend lives in another state. When she came here for visits, she had to pretend to be married after her divorce. I do not understand.