Hell= Grave in the Bible
Malachi 4:3
And ye shall tread down the wicked; for they shall be ashes under the soles of your feet in the day that I shall do this, saith the Lord of hosts.
Sorry, no.
While the Old Testament has reference to the grave, pit, and Hell, the context has to determine what is in view.
In view is the Return of Christ, and as mentioned in the post you ignored to offer up yet another proof text is that Christ taught about Hell and He did not make it to mean simply the grave or physical death itself:
Matthew 10:28
King James Version
28 And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell.
Luke 12:5
But I will forewarn you whom ye shall fear: Fear him, which after he hath killed hath power to cast into hell; yea, I say unto you, Fear him.
If the Lord had meant to lay again the foundational principles of death He would have used the word Hades, and that would have been the equivalent to the limited understanding men had from the revelation provided in the Hebrew Scriptures.
That the enemies of Christ will be His footstool is no more commentary on the Everlasting Punishment He taught than your proof text.
We must distinguish between physical death when it is spoken of in Scripture and Everlasting Death, which is everlasting separation from God.
Men are dead when they are born because they are born separated from God. The only means of Eternal Life (contrasted with everlasting life, which is what Adam would have had if he had remained in the Garden with access to the Tree of Life) is by eating the flesh and drinking the blood of Christ, or in other words—believing in Jesus Christ:
John 6:53
Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you.
Christ's teaching still denies yours: men are to fear God because He can cast into Hell after He has killed.
And destroy both soul and body in Hell.
The destruction is not a cessation of existence, but a state of separation from God that will be everlasting.
Do you also try to teach people they can be in relationship with God through the Covenant of Law? Instead of the teaching of the New Testament that shows men can only be in relationship with God through the New Covenant?
That is what you are doing with proof texts that try to make the statement of the Old Testament negate the teaching of the New.
We know far more about the Resurrection of the dead because of the New Testament, and in no way does Christ's teaching get cancelled out:
John 5:29
And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation.
Two peoples, lost and saved.
Two resurrections, unto life—and unto damnation.
When Christ returns there will certainly be a physical fulfillment of Old Testament Prophecy and teaching, but that doesn't mean we ignore the teaching of Christ and the Apostles, or even the Prophets.
And we certainly do not call Christ's teaching a doctrine of Satan.
God bless.