Sure he was. I agree. But that's... not all.
Well, right, but really, that's not all. Do you not think Adam repented and believed?
Sure, but I think we disagree on Adam's end really was, and will be. Please allow me to explain:
Adam disobeyed and sinned, for sure, and got what God warned him he would get. But after this ~ from Genesis 3:8 on ~ Adam was repentant; he knew what he had done was wrong. And, although I'm sure he fell short of perfection (as we all do), feared and loved and obeyed God from that point forward. Eve certainly knew God as evidenced in her statement in Genesis 4:1, where, having conceived and borne Cain, she says, “I have gotten a man with the help of the LORD.”
There's actually a promise to Adam and Eve in Genesis 3, and that is that she and he will both have to endure hardship
in this life ~ in a fallen world ~
but it will not last forever, but only for a short time (their earthly lives).
At the very least, we see in Hebrews 11 that Abel was given faith, and in Romans 10:17, Paul tells us that faith comes by hearing. So, who do you think Abel heard the truth about God and His Gospel (which was first revealed to Adam and Eve in Genesis 3:15) from? Well, I guess I just answered that question myself...
I think we'll see both Adam and Eve in the new heavens and new earth.
Grace and peace to you.