I read this again but you are making a circular argument and not making an argument from the text . Both Hebrews 8:6 and 1 John 4:7 use the same verb estin and the syntax is the same. So from looking at both texts I don’t see how you can make an argument for one and not the other since they are constructed the same. I believe you are letting your ideas interfere with what is being said .here is the idea that makes sense based on the various verses, Just as God is love and always will be. When the Bible says God is love, it is an equality, not just something about what He currently does. If that was just meant to say that now, at this moment God is love, it would not express the truth as we understand it, if it just meant that at this time He is love. So the same for being mediator. Saying He is the mediator is not meant as something just in the present. While it is something He has done/acted on. It is more something He is.
The other part of that which no one seems to grasp is what the word "mediator" means. The court person who reconciles the plaintiff and defendant, or both civil parties, so they can approach the judge with an agreement. And from there what it means that He was a mediator using His own blood, and this He did once for all time. Christ only shed His blood once, it is not an ongoing sacrifice that He keeps making. With that one time sacrifice, the Bible says he mediated the new covenant once. There is no need to keep creating the covenant, it is in place.
Can you understand that? The need for a new covenant in His blood, which is now an eternal covenant between man and God mediated once in his blood?
some have confused the word mediator with intercessor or high priest. Now these two jesus does eternally. But these two are different offices
Please ask for clarification, or scripture if you wonder about anything specific
Jim is our Father
Johnny is our son
Jackie is my wife
Joanne in our grandmother
How can any of those people no longer be my present relatives ?