Let's see the consequence of verses containing the word "sea" that leads to Rev 21:1, starting with
Rev 16:
3 The second angel poured out his bowl on the sea, and it turned into blood like that of a dead person, and every living thing in the sea died.
This foreshadows the destruction of the sea. The next verse that mentions "sea" is
Rev 18:
17
In one hour such great wealth has been brought to ruin!’ “Every sea captain, and all who travel by ship, the sailors, and all who earn their living from the sea, will stand far off.
The sea is used for delivering wealth and ruin, Rev 18:
19 They will throw dust on their heads, and with weeping and mourning cry out: “ ‘Woe! Woe to you, great city, where all who had ships on the sea became rich through her wealth! In one hour she has been brought to ruin!’
Rev 18:
21 Then a mighty angel picked up a boulder the size of a large millstone and threw it into the sea, and said: “With such violence the great city of Babylon will be thrown down, never to be found again.
The sea is the destination of violence.
Rev 20:
7When the thousand years are complete, Satan will be released from his prison, 8 and will go out to deceive the nations in the four corners of the earth—Gog and Magog—and to gather them for battle. In number they are like the sand on the seashore.
The enemies are as numerous as the sand on the seashore.
Rev 20:
13 The sea gave up the dead that were in it, and death and Hades gave up the dead that were in them, and each person was judged according to what they had done.
The sea contains the dead.
After all these negative associations of the sea, the relief comes finally in
Rev 21:
1 Then I saw “a new heaven and a new earth,” for the first heaven and the first earth had passed away, and there was no longer any sea.
OP: I would like to suggest the alternative interpretation of the Seas being no more in Rev 21:1 as referring to the same Seas in Gen 1:10.
The word "sea" appears 22 times in Revelation. It is a key element in this book symbolizing violence, death, and ruin. It is not referring to the good sea in Gen 1:10.