Either you did not say this right or you have misunderstood something somewhere...
The 'Day of the Lord' is both - 1000 years - and, the first literal day of those 1000 years. Which it is depends on context in scripture.
Jesus returns - and the 7th trumpet sounds -
on that first literal day. His return is precisely what
defines the 'Day of the Lord'.
If you are saying that Jesus returns on the first literal day of the 7th trumpet, I think we disagree. The 7th trumpet blows for an extended period of time. As I explain elsewhere, the 7th trumpet includes all the Bowls. We are shown that the Lord returns at the 7th Bowl, Rev 19. We are shown that the Kingdom of the Lord is declared at the 7th trumpet. But at the start of the first sounding of the 7th trumpet the Lord hasn't returned yet. Why? Because God has not made His enemies His footstool yet. Therefore the 7th trumpet must extend over a period of time to include the Bowls.
Here is the 7th trumpet passage from Rev 11 below. I included verse 12 which refers to the 2 witnesses being called to heaven. You can see that their enemies saw them. These are the same enemies as the Lord's enemies
so these enemies are still present at the start of the 7th trumpet.
12 And they heard a loud voice from heaven saying to them, "Come up here." And they ascended to heaven in a cloud, and their enemies saw them.
13 In the same hour there was a great earthquake, and a tenth of the city fell. In the earthquake seven thousand people were killed, and the rest were afraid and gave glory to the God of heaven.
14 The second woe is past. Behold, the third woe is coming quickly.
15 Then the seventh angel sounded: And there were loud voices in heaven, saying, "The kingdoms of this world have become the kingdoms of our Lord and of His Christ, and He shall reign forever and ever!"
16 And the twenty-four elders who sat before God on their thrones fell on their faces and worshiped God,
17 saying: "We give You thanks, O Lord God Almighty, The One who is and who was and who is to come, Because You have taken Your great power and reigned.
18 The nations were angry, and Your wrath has come, And the time of the dead, that they should be judged, And that You should reward Your servants the prophets and the saints, And those who fear Your name, small and great, And should destroy those who destroy the earth."
19 Then the temple of God was opened in heaven, and the ark of His covenant was seen in His temple. And there were lightnings, noises, thunderings, an earthquake, and great hail.
Do you see any description of the Lord actually returning to earth in the above verses? I don't. Keep in mind that
time is a dimension. It has no definition in space which is where heaven is likely located. So to God one earth day can be 1,000 years and vice versa.
Let's study what we are told is happening during the 7th trumpet:
1. The kingdom of the world has become the kingdom of our Lord and Christ - Declared in Heaven
2. He (Christ) shall reign forever and ever
3. The 24 elders fell on their face and worshiped God
4. The 24 elders gave thanks to the one who is, was, and is to come because He has taken His great power and reigned
5. Nations were angry And Your wrath has come
6. And the time of the dead, that they should be judged
7. That God would reward His servants, the prophets and saints and those who fear God's name both small and great
8. And should destroy those who destroy the earth
9. The Temple of God in heaven was opened and the Art of the Covenant was seen.
10. There were lightnings, noises, thunderings, and earthquake, and great hail.
Those are a lot of events for one single earth day. Yet, all these things are associated with the 7th trumpet. Let's dig deeper on some of these.
3. The 24 elders fell on their face and worshiped God. These same 24 elders fall down and worship Him again in Rev 19:4
5. Nations were angry And Your wrath has come. We know that God's Wrath are the 7 Bowls. Therefore the wrath is not completed until the 7 bowls are poured out.
6. And the time of the dead, that they should be judged. The dead unbeliever is not judged until the end of the millennial reign.
7. That God would reward His servants, the prophets and saints and those who fear God's name both small and great. This same scene is repeated in Rev 19:5
8. And should destroy those who destroy the earth. We know they are not destroyed until after Armageddon. There is no other battle after the 6th trumpet until Armageddon at the 7th Bowl.
10. There were lightnings, noises, thunderings, and earthquake, and great hail. - This ties exactly to the description of the 7th Bowl which is poured into the Air - The Air from where Jesus comes.
We know from Rev 1:10 that John was in spirit in heaven on the "Lords Day."