[
Just focusing on this statement .... if the soul is no more upon death of the body what is there to annihilate?
The meaning of words in the Bible can differ based on the context. In the case of creation of Adam, when God breathed His spirit into Adam's body he became a "living soul". Departure of the ghost from the body suggest reversal of this process. In this context, soul suggests something along the lines of "living/sentient component within a physical body".
However, "fear the one who can destroy both the body and the soul in hell", suggests different meaning for "soul" since the context tells us the body is dead, so here meaning of the soul more along the lines of "invisible, spiritual component of a human being".
"The soul that sins shall die" or " that soul shall be cut off from his people" suggests yet another meaning for soul - more along the lines of
"an individual".
Especially in the light of the last, the Bible does tell us what is annihilated: their NAMES (identities) are blotted out (obliterated) from the book of life. To reinforce this point, the believers are said to receive a new name (new identity) in Jesus Christ! I believe this is one of the main informations that we have for the second death vs the second resurrection. I do not understand how exactly will this play out, maybe I will in time.
As a response to your post quoted below, soul or spirit likely do not belong to the empirical matter/energy realm where everything is lossless and just changes shape, so to say. Being is caused by the breath of the Spirit of God and God (unlike matter-energy world) who is an absolute being in whom we also have our being, cannot be empirically tamed for observation and measurement. I'd think you would concur that God is Spirit, who is above mere energy.
As to the matter, the body is said to be destroyed by decomposition, as long as the Bible is concerned "the dust (physical body that Spirit was breathed into) returns into dust (decomposes)", so this doesn't contradict science. Again, although the word annihilate has "nihil"/"nothing" in it, the word itself doesn't actually suggest something turning into nothing, but destruction. However, "blotting one out" does strongly suggest erasure.
Things to consider.....
Dust is matter, even fire changes matter to other molecules which disperse into the air, so again no annihilation can be inferred from fire if we are to glean spiritual truth from the physical nature of fire it would not be annihilation
Death is cessation of activity of the physical body, death can also mean inoperative
Death in context, according to the classical meaning of the word is also "separation" when referring to soul and spirit
No where has scripture shown that the dead are unconscious... Lazuras and the rich man demonstrate the opposite
This is where the scripture gets "flattened" by applying one semantic to all places
Do you think the soul is able to exist outside of the body?
If the soul is only material/matter as the atheists claim then we have a problem.