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 .
Jim is Father
Johnny is my son
Jackie is my wife
Joanne in our grandmother
How can any of those people no longer be my present relatives ?
Excellent observation!Why does forever mean forever if present doesn’t mean in the present ?