In the Bible the word "HEAVEN" symbolically represents a government, and the word "EARTH" symbolically represents stabilized human society. The word "SEA" symbolically represents restless, tumultuous mankind. The latter are the ones you see carrying picket signs, and protesting. (Isaiah 57:20).
When the Bible speaks about "A NEW HEAVEN" it is referring to God's heavenly based Kingdom/Government that will soon take full control over Earth's affairs to the benefit of obedient mankind and the literal natural earth. God's heavenly based Kingdom/Government or the "NEW HEAVEN", it itself will be a Theocracy, a universal Government with one set of laws, standards and principles for all mankind.
When the Bible speaks about "A NEW EARTH", it's referring to a new earthly society of mankind that will willingly worship and serve God His way, minus all the wickedness and suffering that we see today. The Bible says at Isaiah 11:9 - "They will not cause any harm or any ruin in all my holy mountain, because the EARTH 🌍🌎 will certainly be filled with the knowledge of Jehovah as the waters cover the sea.".
The "SEA" mentioned at Revelation 21:1 symbolically represents "wicked" mankind that will soon be destroyed during the Great Tribulation and Armageddon. (Isaiah 57:20).
