Well thank you for pointing that out, but nobody said it’s the same thing so idk why you brought that up.

If the nails replace the part of Angrons brain that deals with emotional response, then how could he have been calmed without monumental pain?

In fact how could he be calmed at all? The fact that he was claimed shows that The Gestalt directly altered how the nails affected his brain, either blocking or dampening their influence. Either way it altered the machine and gave Angron peace for a moment.

The Emperor says that he could easily remove the nails, but when pressed He lets Arkhan answer his own question. This isn’t The actual answer though, perhaps it was time constraints, perhaps it was due to the uncertain nature of what kind of person Angron would be once the nails were removed and his brain either regrew or was replaced, it’s entirely possible that the Emperor saw that Angron was a Bloodthirsty warrior who was able to stand up and swing an ax, and so therefore could render planets Compliant, remember that the Emperor from his own lips stated that he wasn’t looking for anything other then Generals.

Also your comment about how Arkhan possibly felt was appropriate to refer to something sounds plausible until you remember that of the two he was the one who referred to Angron by name, And continuously referred to him by his name the entirety of the exchange.

Again, that same old tired argument, the Emperor is and always was a god, it doesn’t matter what he said contrary to that fact because he proved it multiplied times.

For instance, if a duck walks like a duck, quacks like a duck, is treated like a duck, everyone knows that it is a duck, then obviously it is a duck.

It doesn’t make it a dog simply because you say that it is.