I think the meaning of chosen is not that God picks some to save and not others based on some inexplicable criteria, or just His whim.
I think what it is, is that God chose to save those whom He foreknew would accept the gift of salvation were it offered to them, as opposed to letting them go to hell for their sins as they deserved.
I don’t know if that gets across the distinction that I am trying to make, but there’s a difference.
The Lord is not slow in keeping his promise as some count slowness, but is patient toward you, not wishing for any to perish but for all to come to repentance.
Romans 10,
...whoever calls on the name of the Lord shall be saved.
...
...faith comes by hearing, and hearing by the word of God.