I started to disagree with you on this point.
Revelation 21:8 But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death.
It then occurred to me that those in the lake of fire will be alive there for all of eternity
While I am not going to get into your error on what you believe about Revelation 21:8, you obviously do not understand that what Paul said about "the last enemy that shall be destroyed is death" is not referring to the judgment of the wicked but rather it has to do with those in the church who will be alive and waiting for his return when he returns.
Who was Paul writing his letter of 1 Corinthians 15 to, was it for the wicked or the church?
In other words, death being put under the feet of Christ is for the church and only benefits the church and it is not for the wicked who are themselves God's enemies.
For the reason why born again believers will die physically is because although sin has been circumcised from their hearts, they still have sin dwelling within their flesh and that sin is what causes their physical death.
Therefore they die physically, but when Jesus returns in the clouds and all other enemies of God associated with sin are made inoperative by Jesus putting them under his feet, then the sin remaining within believers will also be removed and after this the last enemy of death will be made inoperative within those who are alive and waiting for his return as well.
This is what Paul is saying all of this for, for the whole chapter is about the final resurrection and of which the rapture will follow with
Therefore the believers are the ones that Paul's words "the last enemy that shall be destroyed is death" apply unto and not the wicked, for the wicked will die the second death because they themselves are God's enemies and therefore their death is not an enemy of God but rather what God allows for them as their punishment because of their willful sin against him.
You need to see the facts, for what Paul wrote in 1 Corinthians 15:22-26 and 51-58 was in reference to the church and not the the wicked with the exception that the wicked are themselves both God's enemies because they will not repent from their sins and believe.