First, I note that both texts quoted by the OP use the Textus Receptus. "Lord" does not appear in UBS5/NA28 text nor the Byzantine text of Rev 19:1. The source of "Lord" here is possibly a copy of the same idea in V6.
Further, the doxology to the Lord's prayer in Matt 6 is a feature of the Byzantine text and not the NA28/UBS5 text.
However, for the sake of this question let us assume the TR is correct.
Of course, the doxology of Jesus' model prayer is affirmed in many places such as:
- Rev 19:1, 6 - After this I heard a sound like the roar of a great multitude in heaven, shouting: “Hallelujah! Salvation and glory and power belong to our God! ... “Hallelujah! For the Lord our God the Almighty reigns. Let us rejoice and be glad and give Him the glory.
- Rev 16:7 - And I heard the altar reply: “Yes, Lord God Almighty, true and just are Your judgments.”
- Rev 15:3, 4 - and they sang the song of God’s servant Moses and of the Lamb: “Great and wonderful are Your works, O Lord God Almighty! Just and true are Your ways, O King of the nations! Who will not fear You, O Lord, and glorify Your name? For You alone are holy. All nations will come and worship before You, for Your righteous acts have been revealed.”
- Rev 11:15 - The kingdom of the world has become the kingdom of our Lord and of His Christ, and He will reign forever and ever.”
- Rev 4:11 - “Worthy are You, our Lord and God, to receive glory and honor and power, for You created all things; by Your will they exist and came to be.”
- Rev 5:13 - “To Him who sits on the throne and to the Lamb be praise and honor and glory and power forever and ever!”
Interestingly, similar praises are offered to Jesus as the Lamb on the throne:
- Rev 15:3, 4 - and they sang the song of God’s servant Moses and of the Lamb: “Great and wonderful are Your works, O Lord God Almighty! Just and true are Your ways, O King of the nations! Who will not fear You, O Lord, and glorify Your name? For You alone are holy. All nations will come and worship before You, for Your righteous acts have been revealed.”
- Rev 12:10 - “Now have come the salvation and the power and the kingdom of our God, and the authority of His Christ.
- Rev 11:15 - The kingdom of the world has become the kingdom of our Lord and of His Christ, and He will reign forever and ever.”
- Rev 5:12 - “Worthy is the Lamb, who was slain, to receive power and riches and wisdom and strength and honor and glory and blessing!”
- Rev 5:13 - “To Him who sits on the throne and to the Lamb be praise and honor and glory and power forever and ever!”
I also note that following the Lamb's enthronement described in Rev 5, the throne is subsequently described as as jointly belonging to God and the Lamb in:
- Rev 22;1 - Then the angel showed me a river of the water of life, as clear as crystal, flowing from the throne of God and of the Lamb
- Rev 22:3 - No longer will there be any curse. The throne of God and of the Lamb will be within the city, and His servants will worship Him.
