Then where does "patience" come into play? If you knew exactly what was about to happen, you don't have to have patience in waiting for it. You only need patience if you don't know whether it will happen or not.
But see God does know all things that will happen, or God would not be God. All things exist for and are for God, of Him, to Him, through Him are all things. So we can understand God has a plan, and part of His plan is to reveal His glorious nature in the way He works both judgement and mercy. That Peter verse is showing God's patience for His elect, as we are not consumed due to our evil behaviors provoking God, because God is merciful towards those that will be saved. That verse simply exposes a quality of God, that He is patient. God certainly put up with the evil in the world of Noah's day, delaying His eventual judgement. God lets bad things happen, to 'fill up the measure of their sins' for those He know will never be saved.
NT verse
1 Thessalonians 2:16
forbidding us to speak to the Gentiles that they may be saved, so as always to fill up
the measure of their sins; but wrath has come upon them to the uttermost.
OT verse
Genesis 15:16New King James Version (NKJV)
16 But in the fourth generation they shall return here, for the iniquity of the Amorites
is not yet complete.”
Words of Christ
Matthew 23:31-33New King James Version (NKJV)
31 “Therefore you are witnesses against yourselves that you are sons of those who murdered the prophets.
32 Fill up, then, the measure of your fathers’
guilt.
33 Serpents, brood of vipers! How can you escape the condemnation of hell?
God's patience regarding the elect who receive His mercy, and the rebels who are prepared for destruction.
Romans 9
22
What if God, wanting to show
His wrath and to make His power known, endured with much longsuffering the vessels of wrath prepared for destruction, 23 and that He might make known the riches of His glory on the vessels of mercy, which He had prepared beforehand for glory, 24 even us whom He called, not of the Jews only, but also of the Gentiles?