I wish I could help. Since I and my wife were Jehovah's Witnesses themselves, I know how difficult it is to have a real conversation with a Jehovah's Witness. Shortly before I separated from the Watchtower Society, I emailed a few times with my best friend (who is also JW) to draw his attention to some inconsistencies in the Watchtower Society teaching. From then on I noticed that you were literally biting on granite (although he was never completely uncritical either). Another time I tried to talk to my grandmother about it, even then I bit like on granite. She didn't listen to me at all, which made me pretty angry and I started to get loud (and basically I was affirming the Watchtower Society by doing so, because I was fulfilling the classic clichÃ© of the unrestrained renegade and the meek Jehovah's Witness, who can't be disturbed by anything).
Do you know when it really "click" did to me? When I realized that Jesus never rose from the dead as a spiritual being, but with his carnal body, in which he also died. The Watchtower Society skilfully developed this doctrine of the resurrection of Jesus as a spirit being. Anyone who enters into a study with Jehovah's Witnesses will sooner or later be confronted with this teaching. Accepting this satanic false doctrine has several effects on the student – once he feels himself to be "the knowledgeable", since actually only the Watchtower Society brings this doctrine and thus says: "Look here! Only we have the true, deep knowledge. All other Christian communities teach a false resurrection of Jesus Christ!". The student feels as if he is superior to other Christians now that he knows things in which all others are wrong.
Second and most important is that the sacrifice of Jesus Christ can be skillfully distracted from now on, because as Paul argues in the 1st Corinthians, everything depends on the right resurrection of Jesus Christ (I'll write more about this below).
However, the student must first be prepared to accept such a basically insane teaching. He must first be "inoculated" with an uncritical spirit (especially if he comes from another Christian community), and the Watchtower Society achieves this in its studies by first initiating the student into what is for the most part a new mystery: Jesus did not die on the cross, but on the stake.
The Watchtower Society exercises this almost banal subject to the point of no longer going with the student. Basically, it is completely irrelevant to the meaning of the death of Jesus Christ whether he died on a cross or on a stake. But why does the Watchtower Society still attach so much importance to it? Because it knows how our brain works! Everyone knows the proverb: "Anyone who lies once will not be believed if he also speaks the truth". Our brain is trained to recognize patterns that are as similar as possible.
If, for example, we talk to a person and discover in the course of the conversation that he contradicts himself or that he is lying, then we look for further lies or contradictions in the course of the conversation. Everything that our conversation partner tells us from this moment on, no matter how honest it is, we will accept continuously only with suspicion and reservation. The opposite case happens in the same way. If we trust a conversation partner, because we couldn't find any inconsistencies with him, then we become more and more trusting, i.e. he can basically serve us up all sorts of clever lies at some point, our brain will hardly consciously perceive them anymore.
The Watchtower Society, through a skilful argumentation, attaches great importance to persuading the student to believe that Jesus did not die on a cross but on a stake. The Watchtower Society skillfully accuses all other Christian communities of deliberate lying by basically claiming that all other communities know exactly that Jesus died on a stake, only the Watchtower Society honestly admits this and has therefore corrected its teaching to this effect (for it is hardly forgotten to point out that Jehovah's Witnesses also believed in the cross earlier). This kind of skilful manipulation the student encounters again and again: "Earlier Jehovah's Witnesses also celebrated Christmas until they realized it was wrong" etc.)
If he believes these arguments, it is because he thinks again: Man, oh man! The Watchtower Society is really honest. While all Christian communities insist on their error, the Watchtower Society changes immediately when it discovers a new "truth"! From this point on, the Spirit is receptive to lies when they are cleverly wrapped, as it becomes less and less critical. The reason for a thoroughly satanic doctrinal building has been laid, and the student will hardly be able to resist it, since mainly people study with Jehovah's Witnesses who have virtually no biblical knowledge at all, and to whom, accordingly, one lie after another can be told.
But now I would like to go into Paul's Letter 1 to Corinthians, which you cited on your website, because Paul's way of argumentation also points to how Jesus must have risen from the dead:
21 For because in the wisdom of God the world did not know God by the wisdom of God, it pleased God to save the believers by the folly of preaching; 22 because both Jews demand signs, and Greeks seek wisdom; 23 But we preach Christ as crucified, an offence to the Jews, and a foolishness to the nations; 24 but to the called themselves, both Jews and Greeks, Christ, God's power and God's wisdom; 25 for the foolishness of God is wiser than men, and the weakness of God is stronger than men.
Paul writes that he preaches the crucified Christ to both the Jews and the nations. He writes that the nations regard it as foolishness. But what did they consider foolishness? That a man died on a cross? Certainly not that they knew of the Romans. But they consider it foolishness that a man rises from the dead.
For did not the pagans (e.g. the Greeks) believe in the immortality of the soul? It was precisely this teaching of the Greek philosopher Plato, who lived between 427 and 347 B.C., that was widespread at the time. Didn't the pagans believe that when a person dies, a part of him lives on? Could they then really regard it as folly if Paul taught them what the Watchtower Society teaches us – namely that Jesus was not raised invisibly as a human being but as a spirit being? That would never have been foolishness for them – on the contrary, it almost corresponded to their faith. But they did not believe in one thing: that a human being would come to life again as a human being. For the Jews this was a nuisance, but for the Gentiles it was impossible. They would laugh at anyone who told them something like that and label him a lunatic. Such a thing has never happened before and contradicted the then usual and logical view about death and its consequences. Everyone believed in living on after death, but a resurrection from the dead was impossible and ridiculous for them.