The Lord’s Day in the Bible is one day in the future, not a weekly day. It isn’t a restful day as the Sabbath is supposed to be, it is a day of despair. All these prophet passages point to how terrifying it is.
The Sabbath hasn’t changed. There are no Scriptures backing up a change in the Sabbath. The only thing I have seen is taking Acts 20:7 out of context to support this change. If I met with another believer on a Tuesday, does that mean Tuesday is now the Sabbath? Why because Paul and some other believers got together on Sunday does that change the Sabbath? The Sabbath isn’t even mentioned here in this verse.