The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, """not willing that any should perish, but that all should come to repentance." (2Pet 3:9"""===God's will for ALL but still your choice.
About your last phrase "God's will for ALL but still your choice" I'd agree with what you seem to refer to in the "will" of God here. It is his
preceptive will, what he prescribes for man to do for salvation; so I agree there. Now, as to "but still your choice", how and
why does a person make that choice, believe unto salvation? Paul tells us as recorded by Luke:
"When the Gentiles heard this, they were glad and praised the word of the Lord; and
as many as had been destined for eternal life became believers." (Acts 13:48 NRSV)
Faith is God's gift:
"For he has graciously
granted you the privilege not only of believing in Christ, but of suffering for him as well—" (Phil 1:29 NRSV)
"Therefore, my beloved, just as you have always obeyed me, not only in my presence, but much more now in my absence, work out your own salvation with fear and trembling; for
it is God who is at work in you, enabling you both to will and to work for his good pleasure." (Phil 2:12-13 NRSV) *
If it is God's "enabling" the Christian; how much more enabling is required for the one "dead" in sins?
"For by grace you have been saved through faith, and this is not your own doing;
it is the gift of God—" (Eph 2:8 NRSV)
Albert Barnes gives a good parabolic understanding of this passage concerning God's will here:
"One may have a sincere desire that others should not perish, and yet it may be that, in entire consistency with that, they will perish. A parent has a sincere wish that his children should not be punished, and yet he himself may be under a moral necessity to punish them. A lawgiver may have a sincere wish that no one should ever break the laws, or be punished, and yet he himself may build a prison, and construct a gallows, and cause the law to be executed in a most rigorous manner. A judge on the bench may have a sincere desire that no man should be executed, and that everyone arraigned before him should be found to be innocent, and yet even he, in entire accordance with that wish, and with a most benevolent heart, even with tears in his eyes, may pronounce the sentence of the law."
"Say unto them, As I live, saith the Lord GOD, I have no pleasure in the death of the wicked; but that the wicked turn from his way and live: turn ye, turn ye from your evil ways; for why will ye die, O house of Israel?" (Ezek 33:11 KJV)
There is a second understanding of this difficult verse that is held by many 'Calvinists' as in:
John Gill: "
not willing that any should perish; not any
of the us, whom he has loved with an everlasting love, whom he has chosen in his Son, and given to him, and for whom he has died, and who are brought to believe in him."
Matthew Poole: "
Not willing that any should perish;
any that he hath ordained to life, though not yet called."
The idea of a sinner having "free will" to make this choice to believe on his own is contrary to so many verses on the question of belief.