Someone who is not covered by Christ will be eternally in their own soul/spirit without a body that can be physically burned.
No. The resurrection of the unsaved proves they will have bodies. And since they are not saved, they do not get immortal bodies. That's why so many scriptures say they will be destroyed, consumed and vanish away because that's what happens in a cremation.
"The soul that sinneth,
it shall die." Ezekiel 18:4.
"He that overcometh shall not be hurt of
the second death." Revelation 2:11
"And death and hell were cast into the lake of fire. This is
the second death. And whosoever was not found written in the book of life was cast into the lake of fire." Revelation 20:14,15.
"The earth and all the inhabitants thereof
are dissolved." Psalm 75:3.
"Let the sinners be consumed out of the earth, and let
the wicked be no more." Psalm 104:35.
"Consume them in wrath,
consume them, that they may not be." Psalm 59:13.
"The Lord preserveth all them that love him: but
all the wicked will he destroy." Psalm 145:20
"When the wicked spring as the grass, and when all the workers of iniquity do flourish;
it is that they shall be destroyed for ever: Psalm 92:7
"For, behold, the day cometh, that shall burn as an oven; and all the proud, yea, and all that do wickedly,
shall be as stubble; and the day cometh that shall
burn them up, saith the Lord of hosts, that
it shall leave them neither root nor branch." Malachi 4:1
"And the destruction of the transgressors and of the sinners shall be together, and
they that forsake the LORD shall be consumed." Isaiah 1:28
"Enter ye in at the straight gate: for wide is the fate, and broad is the way, that
leadeth to destruction, and many there be which go in thereat." Matthew 7:13
"But the wicked shall perish, and the enemies of the LORD shall be as the fat of lambs:
they shall consume; into smoke shall they consume away." Psalms 37:20