Interesting question.
2 Peter 3:9. “The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish, but that all should come to repentance.”
I think God has the desire but has not put His force of will behind it. "All should come" is not the same thing as saying "All will come". We have the ability to choose.
In Elizabethan English, will is want, wont is know, and should could be will or want...
Let's try Young's Literal:
2Peter3:9 the Lord is not slow in regard to the promise, as certain count slowness, but is long-suffering to us, not counselling any to be lost but all to pass on to reformation...
If God has the ability and the desire to change people's hearts, then this is what
God wants, wills, shoulds, and knows.
Any alternative makes no sense. To have a hard heart is to have no ability
to comprehend what joy lies in having a soft heart, open to God's Grace.
It would be like telling someone that the only way to escape a fire is through a
particular door, but then refusing to provide a key to open the door, even though
you are standing right next to the victim with the key in your pocket, watching
them suffer.