Muddying the waters somewhat is that I have read that the Romans - and probably other cultures too - did not adhere to a seven day week always.
Continuing the previous thought:
Publius (or Gaius) Cornelius Tacitus (AD 56 - after AD 117)
The Histories of Tacitus; Books III, IV, And V. with introduction and notes by A. D. Godley, M.A. Fellow of Magdalen College, Oxford. London Macmillan and Co., Limited; New York: The Macmillan Company. 1907.
Historarium Lib. V. [Line 15 and onward]
"...
[Page 148; Internally Page 127; IV. Line 15; Beginning 3rd Word] alii honorem eum Saturno haberi, seu principia religionis tradentibus Idaeis, quos *** Saturno pulsos et conditores gentis accepimus, seu quod de septem sideribus, quis res mortales reguntur altissimo orbe et praeceipua potentia stella Saturni feratur ac pleraque caelestium vim suam et cursus setptenos per numeros compleant. ..." [Page 148; Internally Page 127] -
https://archive.org/stream/histories.../n148/mode/1up
"... [Page 290; Internally 269] Notes, V. Chap. 4. ... 17.
Saturno: the Greeks and Romans had adopted the Egyptian custom of naming days after the planets, and the day of Saturn corresponded to the Jewish Sabbath. ..."
[Page 290; Internally 269] -
https://archive.org/stream/histories.../n290/mode/1up
English translation – Sourced - http://www.eliyah.com/lunarsabbath.html
“... They are said to have devoted the seventh day to rest, because that day brought an end to their troubles. Later, finding idleness alluring, they gave up the seventh year as well to sloth.
Others maintain that they do this in honor of Saturn; either because their religious principles are derived from the Idaei, who are supposed to have been driven out with Saturn and become the ancestors of the Jewish people; or else because, of the seven constellations which govern the lives of men, the star of Saturn moves in the topmost orbit and exercises peculiar influence, and also because most of the heavenly bodies move round their courses in multiples of seven. ...”
Even
Josephus lived during the Roman occupation of Judaea and has a pretty good record of chronology.
Then there's the Sun standing still in the OT... how did THAT affect the flow of time?
Did it say anywhere that the day (24 hrs) was longer, or is it possible that the daylight portion (normally 12 hours) of the 24 was longer than normal, with a shorter night (like in Alaska, North and South Poles)? Also, did you read the counterpart of the sundial in reverse in 2 Kings 20:11; Isaiah 38:8? Also, we have the record of both events, and chronology takes into account those events as recorded. Just because the daylight portion of the day was longer does not displace time. It only displaces light and dark in that day (24 hrs). I hope that has been clarified for you and all.
Most of the "muddying the waters" are simple atheistic (or Bible skeptics) arguments against the scripture and are easily shown to be spurious, or non-existence issues.
So anyone who says you HAVE to worship on a certain day or else is just wrong. They cannot even prove they are worshiping on that day themselves.
That is again the misunderstanding of when "worship" takes place. It is to be 24/7/365. The issue of the OP is in regards what day is "the Lord's day" as identified in scripture. The topic of the OP is not even discussing what takes place so much upon that day, such as the "rest" verses common labour of the other 6 days, however, I am glad we can discuss it here anyway.
Final thought: the phrase "the day of the Lord" can mean several different things in the Bible which can be confusing.
Actually the text in Revelation 1:10 doesn't say "the day of the Lord". It says "the Lord's day", which is even in a different construct in koine Greek and English from "the day of the Lord".
Consider the language itself, “τηG3588 T-DSF κυριακηG2960 A-DSF ημεραG2250 N-DSF”, as the word "κυριακη" (transliterated "kuriake") is an Adjective - Dative - Singular - Feminine., thus used as a 'possessive' ("of", see 1 Corinthians 11:20, "the Lord's supper"), and not like the phrase "day of the Lord" (ἡμέρα κυρίου) which is in the genitive masculine (see 2 Peter 3:10, &c; see also so called septuaginta (lxx) uses), which John calls the "great day of God Almighty” (Revelation 16:14). Revelation 1:10 - I was in the Spirit on the Lord's day, and heard behind me a great voice, as of a trumpet,
Revelation 1:10 - εγενομην εν πνευματι εν τη κυριακη ημερα και ηκουσα οπισω μου φωνην μεγαλην ως σαλπιγγος
Revelation 1:10 - I wasG1096 inG1722 the SpiritG4151 onG1722 theG3588 Lord'sG2960 day,G2250 andG2532 heardG191 behindG3694 meG3450 a greatG3173 voice,G5456 asG5613 of a trumpet,G4536
Revelation 1:10 - εγενομηνG1096 V-2ADI-1S ενG1722 PREP πνευματιG4151 N-DSN ενG1722 PREP τηG3588 T-DSF κυριακηG2960 A-DSF ημεραG2250 N-DSF καιG2532 CONJ ηκουσαG191 V-AAI-1S οπισωG3694 ADV μουG1473 P-1GS φωνηνG5456 N-ASF μεγαληνG3173 A-ASF ωςG5613 ADV σαλπιγγοςG4536 N-GSF
Isaiah 58:13 - "the Lord's holy day", the seventh day of the week, the sabbath of the Lord.
Isaiah 2:12, 13:6,9, 34:8 – “the Day of the LORD”, the final eschatological climaxing day:
Deut. 31:17-18, 1 Sam. 3:12, 8:18, 1 Ki. 22:25, 22:35, 2 Chr. 18:24, 18:34, Job 3:3-4, 21:30, Psa. 110:5, Isa. 2:11-12, 17, 20,3:7, 3:18, 4:1-2, 5:30, 7:18,21,23, 10:20,27,32, 11:10-11,16, 12:1,4, 13:6,9,13, 17:4,7,9, 19:18-19,21, 23-24, 20:6, 22:12,20,25, 23:15, 24:21, 25:9, 26:1, 27:1-2,12-13, 28:5,19, 29:18, 30:23,25, 31:7, 34:8, 52:6, 58:5, 61:2, 63:4, 66:8, Jer. 1:10, 4:9, 25:33, 30:8, 31:6, 39:17, 46:10, 49:22,26, Lam. 1:12, 2:1,21-22, Eze. 7:7,12,19, 13:5, 22:24, 24:27, 27:27, 29:21, 30:3,9,18, 38:14,19, 39:11,22, 48:35, Hos. 1:5,11, 2:16,18,21, 5:9, 9:5 , Joel 1:15, 2:1-2,11, 2:31, 3:14,18, Amos 1:14, 2:16, 3:14, 5:18,20, 8:3,9-10,13, 9:11, Oba. 1:8,15, Mic. 2:4, 3:6, 4:6, 5:10, 7:11-12, Nah. 3:17, Hab. 3:16, Zeph. 1:7,8,9,10,14,15,16,18, 2:2-3, 3:8,11,16, Zech. 2:11, 3:9,10, 9:16, 11:11, 12:3,4,6,8,9,12, 13:1,2,4, 14:1,3, 14:4,6,7,8,9,13,20,21, Mal. 3:2,17, 4:1,3,5, Matt. 7:22, 10:15, 11:22,24, 12:36, 24:36,50, 25:13, Mark 6:11,13:32, Luke 6:23, 10:12, 17:24,30,31, 21:34, John 6:39,40,44,54, 8:56, 11:24, 14:20, 16:23,26, Rom. 2:5,16, 13:12, 1 Cor. 1:8, 3:13, 5:5, 2 Cor. 1:14, Php. 1:6,10, 2:16, 1 Thes. 5:2,4, 2 Thes. 1:10, 2:2,3, 2 Tim. 1:12,18, 4:8, Heb. 10:25, Jam. 5:5, 1 Pet. 2:12, 2 Pet. 2:9, 3:7,10,12, 1 John 4:17, Jude 1:6, and Rev. 6:17, 16:14, 18:8.
In the rest of Isaiah, when he refers, by inspiration of the Holy Ghost, to "the Day of the LORD", it is always in a differing phrase and context. See - Isaiah 2:12, 13:6,9, 34:8.
Others say it like this:
"the day of the LORD”
Jeremiah 46:10
Lamentations 2:22
Ezekiel 13:5, 30:3
Joel 1:15, 2:1,11,31, 3:14
Amos 5:18,20
Obadiah 1:15
Zephaniah 1:7,8,14,18, 2:2,3, 14:1
Malachi 4:5
Acts 2:20
1 Corinthians 5:5
2 Corinthians 1:14
1 Thessalonians 5:2
2 Peter 3:10
"the day of their calamity"
Deuteronomy 32:35
"the day of vengeance"
Proverbs 6:34
"the day of the LORD's anger"
Lamentations 2:22
"day of the LORD's vengeance"
Isaiah 34:8
"the day of vengeance of our God"
Isaiah 61:2
"the day of vengeance"
Isaiah 63:4
"the day of the LORD's wrath"
Zephaniah 1:18
"Day of God"
2 Peter 3:12
"great day of God Almighty"
Revelation 16:14
The language is different, as shown in Isaiah 58:13, as compared to Isaiah 2:12, 13:6,9, 34:8. Even John in Revelation makes the same distinction, between "the Lord's day" (Rev. 1:10; "Lord's": Adjective-Dative-Singular-Feminine, acting as a possessive, see 1 Cor. 11:20, "day": Noun-Dative-Singular-Feminine) and "that great day of God Almighty" (Rev. 16:6, "day": Noun-Genetive-Singular-Feminine and "God Almighty": Noun-Genetive-Singular-Masculine). In 1 Cor. 1:8, "day" is Noun-Dative-Singular-Feminine, and Lord Jesus Christ, is Noun-Genetive-Singular-Masculine.
There is a difference between the Adjective and it's use, and the noun and it's use, as well as a difference in the timing of those days
Your statement assumed (before evidence presented) that the phrase "the Lord's day" was "the day of the Lord". No evidence was provided for that assumption, and therefore, I cannot agree with that assumption without evidence.