ohn already set the scene that the Lord's Day involved the Second Coming, and was not a literal day of the week.
Then even the one thing I thought was LITERAL may have actually been SYMBOLIC, making Revelation potentially 100% symbolic.
Why would Jesus send letters to churches on the day of His return? That seems too late to repent and change … so I will stick with Sunday as a POSSIBLE meaning for the day that John received his vision.
FWIW, there's more than one 'day of the Lord' alluded to in the scriptures, and, the day of the Lord is never a good thing if you're on the recieving end of His anger.
Babylon:
1 The burden of
Babylon, which Isaiah the son of Amoz did see.
5 They come from a far country, from the uttermost part of heaven, even Jehovah, and the weapons of his indignation,
to destroy the whole land.
6 Wail ye; for
the day of Jehovah is at hand; as destruction from the Almighty shall it come. Isa 13
Judah:
8 Jehovah hath purposed to destroy the wall of
the daughter of Zion; He hath stretched out the line, he hath not withdrawn his hand from destroying; And he hath made the rampart and wall to lament; they languish together.
22 Thou hast called, as in the day of a solemn assembly, my terrors on every side; And there was none that escaped or remained in
the day of Jehovah`s anger: Those that I have dandled and brought up hath mine enemy consumed. Lam 2
Egypt and those in league with her:
3 For the day is near, even
the day of Jehovah is near; it shall be
a day of clouds, a time of the nations.
4 And
a sword shall come upon
Egypt, and anguish shall be in Ethiopia, when the slain shall fall in Egypt; and they shall take away her multitude, and her foundations shall be broken down.
5 Ethiopia, and Put, and Lud, and all the mingled people, and Cub, and the children of the land that is in league, shall fall with them by the sword. Ezek 30
Nations that did violence to Israel:
14 Multitudes, multitudes in the valley of decision! for
the day of Jehovah is near in the valley of decision.
15 The sun and the moon are darkened, and the stars withdraw their shining.
19 Egypt shall be a desolation, and
Edom shall be a desolate wilderness, for the violence done to the children of Judah, because they have shed innocent blood in their land. Joel 3
Israel:
1 Hear ye this word which I take up for a lamentation over you,
O house of Israel.
18 Woe unto you that desire
the day of Jehovah! Wherefore would ye have
the day of Jehovah? It is darkness, and not light.
19 As if a man did flee from a lion, and a bear met him; or went into the house and leaned his hand on the wall, and a serpent bit him.
20 Shall not
the day of Jehovah be darkness, and not light? even very dark, and no brightness in it? Amos 5
Edom (and other nations?):
1 The vision of Obadiah. Thus saith the Lord Jehovah
concerning Edom: We have heard tidings from Jehovah, and an ambassador is sent among the nations,
saying, Arise ye, and let us rise up against her in battle.
15 For
the day of Jehovah is near upon all the nations: as thou hast done, it shall be done unto thee; thy dealing shall return upon thine own head. Ob 1
Maktesh:
7 Hold thy peace at the presence of the Lord Jehovah; for
the day of Jehovah is at hand: for Jehovah hath prepared a sacrifice, he hath consecrated his guests.
11 Wail, ye inhabitants of Maktesh; for all the people of Canaan are undone; all they that were laden with silver are cut off.
14The great
day of Jehovah is near, it is near and hasteth greatly,
even the voice of
the day of Jehovah; the mighty man crieth there bitterly.
15 That day is
a day of wrath, a day of trouble and distress, a day of wasteness and desolation, a day of darkness and gloominess, a day of clouds and thick darkness,
18Neither their silver nor their gold shall be able to deliver them in
the day of Jehovah`s wrath; but the whole land shall be devoured by the fire of his jealousy: for he will make an end, yea, a terrible end, of all them that dwell in the land. Zeph 1
Exhortation to Repent before the Chaldean Invaders Come. Doom of Judah's Foes, the Philistines, Moab, Ammon, with Their Idols, and Ethiopia and Assyria.
1 Gather yourselves together, yea, gather together, O nation that hath no shame;
2 before the decree bring forth,
before the day pass as the chaff, before the fierce anger of Jehovah come upon you, before
the day of Jehovah`s anger come upon you.
3 Seek ye Jehovah, all ye meek of the earth, that have kept his ordinances; seek righteousness, seek meekness: it may be ye will be hid in
the day of Jehovah`s anger. Zeph 2
Apostate Judaism:
5 Behold, I will send you Elijah the prophet (read
JOHN THE BAPTIST) before
the great and terrible day of Jehovah come. Mal 4