https://www.merriam-webster.com/dictionary/prophecy
Definitions:
1) the inspired declaration of divine will and purpose = God's will to save everyone 1 Timothy 2:3-6
2) a prediction of something to come = When everyone is a believer in Christ 1 Corinthians 15:22-28
God decides when a person realizes the truth. That's why God hardened the Pharaoh's heart Exodus 9:12, God made it so the Pharaoah would not listen.
God also makes other people not listen. So there may be certain times where, someone's not listening because God is making them not listen. Just like how it's by the grace of God we are saved, it's also by His grace when we are saved.
Still, I like evangelizing. Because the Lord can use that to save others. When talking to someone, I tell them the truth. If they are saved at that moment, then it is God's will. If not, then later, it is God's will. It's sorta similar to like... why does God prophesize to people who He knows won't listen at that time? Why did God send Israel prophets knowing they would not listen?
2 Chronicles 24:19 Yet he sent prophets among them to bring them back to the Lord. These testified against them, but they would not pay attention. (ESV)
Christian Universalism is a prophecy, a prediction of a future event.