OSAS is true if a person allows the Spirit to lead them.
But the Bible says that some that were enlightened by the truth went back to doing worldly things like a sow that is clean goes back to wallowing in the mud.
But OSAS is not true that God chooses who will be saved and not saved without their choice.
If that is the case then we are robots that do not make a choice our self.
That would mean God's kingdom is not true love but robotic love, and He is not evil to condemn people that have no choice but to reject the truth.
What would God base His decision on when all people have sinned and come short of the glory of God, and He is no respecter of persons, and there is none that does good, no, not one, and all sin is unrighteousness, and if you broke the least of the law you broke all the law.
You can program your computer to say I love you but does your computer actually love you, and you can program your computer to say I hate you and will you get mad at it and smash it.
When the Bible says the saints are predestined to salvation, and have salvation before the world began means that God already had the plan to give salvation to the people before He started creation but this salvation is to whoever wants this salvation.
Which the Bible says that the Spirit and the bride say Come, and whosoever will can have salvation.
The Bible speaks that someone that has been saved can lose salvation is they do not continue in the goodness of God.
Which some do not continue in the goodness of God but go back to doing things of the world like a sow that is clean goes back to the wallowing in the mud.
The Lord knows them that are His having this seal for this is what seals them that everyone that names the name of Christ depart from iniquity.
Which not everyone that says Lord Lord will be able to enter heaven for they were workers of iniquity.
And Paul said awake to righteousness, and sin not, which some have not the knowledge of God: and he speaks this to their shame.