My Mother and Stepfather (he is the son of a Southern Baptist preacher) do not pray in public. My Dad is Southern Baptist and never prayed (he died last month) before meals, but someone always did at family reunions.
My partner and I basically Unitarian leaning towards pagan, and we don’t pray ourselves in the manner you mean. His parents however are Baptist, and from south Georgia (but are not Southern Baptists, just Baptists who are Southern) and they do pray before all meals, even at restaurants, so me and my partner pray with them when we are.
Off topic generally but relating to my partner’s partents’ church, my partner’s mom outed him to the whole small southern town he is from when her church was discussing its opinion on homosexuality. They came down on the accepting side after some debate.
We personally usually don’t say grace at home or in restaurants unless we’re with fellow church folk or it’s a holiday. However, I’m amazed by how many people here see it as some rare odd thing.
Various portions of my family are Catholic, Dutch reform, Lutheran, and Disciples of Christ. All of them will do a family prayer before eating a meal. Ditto for my husband’s family, which is half Presbyterian and half charismatic evangelicals (wishy-washy Southern Baptist or Church of Christ, depending on how they feel about the pastor).
My husband works for a company owned by Mennonites, and they do group prayers in restaurants. Including at the company parties. Which are dry.
We’re in Illinois. My family is in Indiana. ETA: we’re all white.