Your postulates run contrary to everything Jesus ever said about the gift of salvation freely given to whomsoever in good faith wills to receive Him and it.To believe is a command but it doesn't bring salvation. Salvation is given from the grace of God through Jesus Christ not from believing - belief is a result, not a cause. It's the timing is what I was getting at. To cut to the chase, while there is one salvation, it can be viewed as consisting of two distinct parts - one providing a basis for the other.
The first part is when one is saved during their lifetime spiritually from which they come to belief and demonstrate it; the second part is to actually be saved - experience salvation - from the wrath of God on judgment day. So, when we read "shall be saved" it is speaking about the future salvation on judgment day, and really, that is the important part and the ultimate purpose of salvation. Belief demonstrates that spiritual salvation has occurred because it is its byproduct, but it is not the cause. Salvation happens first, belief follows afterwards
[Rom 5:9 KJV] 9 Much more then, being now justified by his blood, we shall be saved from wrath through him.
[Act 18:27 KJV] 27 And when he was disposed to pass into Achaia, the brethren wrote, exhorting the disciples to receive him: who, when he was come, helped them much which had believed through grace:
They also sound like 10 lbs of bafflegab stuffed into a 5 lbs bag. Just awful to have to trudge through really. Your boss Augustine sounded much more polished and erudite when he was bafflegabbing.
Still just as wrong though.....