And you'd think that since the majority of the authors use the term "kingdom of God", that we would also.
But people's obsession with the idea of a place, has made them think that "heaven" and the "kingdom of heaven" are the same thing.
And they are not.
So when people read "enter the kingdom of heaven", they think it's the same as "go to heaven when you die", but Jesus was talking about entering the kingdom right now.
Be very careful when you read "kingdom of heaven" verses, they do not refer to going to a mysterious place when you die or "get raptured."
And the bible never says you can assume you'll "go to heaven" in the future because you are saved right now, just that you can "enter the kingdom" right now.
Huge misconceptions about what happens when we die, where we live after the resurrection, and so on.
Kingdom of God/Kingdom of Heaven is a different experience of earthly living. And Jesus beat around the bush on it's description with parables, so that people would not simply decide for themselves that they are somehow in it without having a personal witness by experiencing it themselves. And anyone that wants to enter it, has very clear instructions on how to do so. But people are focused on the word heaven instead of the instructions.
Documented plainly in the scriptures -
1. The only way to "heaven" is to be caught up by God (Enoch, Elijah, Paul's acquaintance, for examples), or ascend on your own ability (Jesus, Two witnesses, for examples)
2. "The kingdom of heaven/kingdom of God" are "within you" or "press into you" and is "at hand" or "draws near"
Best to toss out all your teachings about both, grab the bible and a proper cross of bearing other people's burdens and iniquities and seek, ask, find out what the terms mean. Chances are your pastor and youtube, and me have it wrong.