Former SDA here become liberal Protestant (haven't chosen a specific denomination yet. Some quick clarifications: At least according to theologians I was surrounded by, Adventists don't think the dietary laws are still in effect, they think they indicated which foods are unhealthy and see them as divine insight on a matter that Israel couldn't have otherwise known. The laws set a new baseline, almost like the furthest a person could stray away dietarily while still being in God's good graces. What they do think is that the ideal/original diet is a Vegetarian one.

Anyways, very few Christians follow the Saturday Sabbath. There are Seventh Day Baptists (who actually gave SDAs the idea of a seventh day Sabbath in the first place), but that's about it beyond random individuals in other churches who choose to follow it.

That said, I think the Sabbath is becoming a major point of focus in American Christianity today. You cannot attend a seminary anywhere in this country without having it be a point of discussion. At my Seminary it is a topic that came up in every class. The difference is the discussion was never about which day to honor the Sabbath on, it was always about what Sabbath means for Christians today. How should we practice it in terms of how the church represents itself to the wider world, and how does practicing the Sabbath enact God's work in the world as it relates to the restoration of creation, Christian worship and practice, and signals the coming kingdom?

In short, Sabbath theology is immensely rich and worthy of our fixation. It does not have to involve a debate about days at all. I have yet to encounter a Christian who wants to talk about it in terms of why we should do it on Sunday. It's rather: what should we do with it?