Do Protestant writers acknowledge the same?

Answer

They do.
NOTE - "IS there no express commandment for observing the first day of the week as Sabbath,
instead of the seventh day?-None whatever. Neither Christ, nor His apostles, nor the first Christians
celebrated the first day of the week instead of the seventh as the Sabbath."-New York Weekly Tribune,
May 24, 1900.
"The Scriptures nowhere call the first day of the week the Sabbath. . . . There is no Scriptural
authority for so doing, nor of course any Scriptural obligation." The Watchman (Baptist).
"The observance of the first instead of the seventh day rests on the testimony of the church, and
the church alone.' -- Hobart Church News, July 2, 1894.
For additional testimonies, see reading on page 146.

What prophecy was fulfilled in the slaughter of the children of Bethlehem?
What does he find who follows after righteousness?
How is unity preserved in the diversities of gifts?
What was the difference between Cain's and Abel's characters?
How many distinct classes will have a resurrection?
How did Elijah pray before obtaining his request?
Upon what condition does Christ say we shall receive?

Questions & Answers are from the book Bible Readings for the Home Circle