Revelation is written in highly-vivid word pictures not necessarily chronology of the happy climax of Rev 20-22.
If you're uncertain about its contents and chronology, I suggest you refrain from studying it:
Rev 22:18-19 For I testify to everyone who hears the words of the prophecy of this book: If anyone adds to these things, God will add to him the plagues that are written in this book;19 and if anyone takes away from the words of the book of this prophecy, God shall take away his part from the Book of Life, from the holy city, and from the things which are written in this book.
Doesn't Isaiah 57v20 liken the wicked to a restless or troubled sea? So the 'sea' that will be no more will be the wicked sea of mankind. Psalm 92v7....
But we must be careful not to apply metaphors to literal verses. Do a simple search in an online bible for the word "sea" only in the book of Revelation. As you read the passages, replace the word sea with "mankind" or people. Notice how it doesn't make sense. Now, without prejudice, do the same thing but this time interpret the word "sea" literally. You'll notice it makes the meaning so much clearer. In the verses where metaphor is implied, for example, Rev 13:1 and Rev 17:1, you'll notice in both of these passages how other scriptures point out their literal meaning (Dan 7:23-24 and Rev 17:15 respectively) There's no guess work, it just involves some digging. This is a true example of how scripture interprets scripture.
Just like the waters of Rev 17v1 according to verse 15 don't the waters mean people and not literal water?
Yes it does. But as the exercise above proves, applying the same symbolism to every passage with the word sea would be poor exegesis and result in misinterpretation and misapplication of the text.
Doesn't Jesus have subjects from sea to sea to the ends of the earth according to Psalm 72v8 ? Isn't it Jesus who is the one described by Zechariah [9vs9,10] whose dominion will be from sea to sea.....
These are obvious metaphors which illustrates Christ's all-encompassing 1000 yr reign throughout the whole earth. Does this give us permission to take this metaphor and apply it to every scripture containing the word sea?
For example, The book of Genesis symbolically pictures satan as a serpent. Would we then say every serpent mentioned in scripture is symbolic of satan? Of course not. Because in Num 21:7-9 God commanded Moses to set up a replica of a serpent, which was actually symbollic of Jesus Christ! (John 3:14-15), In like manner, your "sea" metaphor cannot apply in every case.
This is a another example of allowing scripture to interpret scripture. I didn't have to read anything into the verses or apply any of my own preconceived notions or beliefs because the meaning was found elsewhere.
Since the earth abides forever- Ecc 1v4 B, then it is not the oceans or literal sea that will be removed but the wicked such as those of Proverbs 2vs21,22 Do you notice who will remain in those verses?
The earth will abide forever but according to Mat 24:35; 1 Pe 3:10-12; and Heb 1:10-12, not in its current form or state.
As Christ implied in Mat 24:35, the current state of the heavens and earth will "pass away" [Greek meaning- "continue for a time" same word is used in Rev 21:1], This implies the heavens and earth will "change" as stated in Heb 1:12. This will involve burning up the contents [elements] of the surface of the current earth including the oceans (Rev 21:1) which science tells us will naturally cause the elimination of the atmosphere [heavens]. These cataclysmic changes will make it impossible for the existence of physical life and pave the way for the New Heavens and New Earth which only righteous spirit beings will inhabit!
If you think about it, both views are correct! The surface of the old heavens and earth will be purged or destroyed (1Pe 3:10-12) only to make way for the new and improved heavens and earth which will be designed to last forever! (Ecc 1:4)