Free will needs something to react to. So people take the announcement "whosoever believes" and turn it into law saying instead "whosoever chooses to believe".
You have a warped view of "The Law". And, it isn't the Old Testament. It was in the New Testament that Jesus spoke that.
If you hear the gospel and believe it, just like you believe the chair you are sitting in is real, it needs no act of the will.
That is not a good analogy, to support your point. Even if I don't believe the chair I am sitting in, exists, it still exists. It isn't any less or more real, because I choose to believe or not. But, if I don't believe it exists, I not only won't sit in the chair, I don't even believe there is a chair there. Instead, I believe you are loopy. You can tell me to sit all you want and if I don't have confidence the chair exists, I would be a fool to sit in it.
Likewise, the Gospel (Good News) is real--whether you or I or any other person believes it is real or not. But, just like that chair, if people aren't willing to make the choice to sit in it--even though it is real--it won't be used. God chose to give us that choice, because God wants willing worshippers who will CHOOSE to not only to accept what He said but who will CHOOSE to invest faith that even when His chair seems hidden, we know it is still there and ACT on that belief. God even helps us with that; but God doesn't make us choose Him.
But here is where many become confused. If you choose to believe, it is because you already believe, or you would not choose to believe. So God already saved them before they chose to believe. Whosoever believes has eternal life.
That is a textbook example of circular reasoning.
Choosing to believe/Accepting God's grace is an attitude. Most people who are choosing to believe would tell you, if you listened, that we could not earn our salvation. If God didn't decide to save some humans and God didn't provide a way and God didn't nudge us here or there, we'd be toast like everyone else. BUT GOD...and therefore my choice matters. If not for God, I can try to save myself from His wrath with all I have, and I can't. I will never, apart from what God did for me, be able to make all my choices in a way to avoid hell--even if I make a few of them correctly here and there. Apart from choosing to accept what God offered, I can't will or choose to get into heaven or have eternal life with Him. I have no power to do that. As a human, apart from His action, I just cannot choose to give myself that grace. But, God can and did. He's the one who turns my corruptible into incorruptible--no amount of willful choices allows me to do that independently of the God who will transform my body in the blink of an eye. He's the One who gives me the Blood to put on my doorposts and the One who gives me His Holy Spirit to serve as my guarantee, my counselor, my comforter, and my guide. He just said I have to choose to genuinely believe to enter in.
Works mentality is a completely different entity. It says I can be good enough that God will owe me salvation and heaven. Works mentality suggests that I am checking all the blocks and therefore God owes it to me that He not only saves me from His wrath, but graces me with His presence and knowledge of Him eternally.
According to God, He looks at the heart.
100% depravity looks like satan and the demons. It looks like those mentioned in 2 Thes 2:10-12. It looks like those before the flood (save Noah and his family) and it looks like old sodom and gemorrah. It looks like those after they take the mark of the beast and worship him. It looks like those who blaspheme the Holy Spirit. It looks like continually wicked. It doesn't look like every walking human being.