It is written (Jeremiah 17), "The heart is deceitful above all things, and desperately wicked: who can know it?" We can look at today's society and see this play out all the time. Misguided people, with good intentions, are often responsible for horrible actions. For instance, some people believe it is okay to march the streets in protest, but in doing so, have no problem vandalizing businesses, regardless of what beliefs the business owners have. The thugs get so worked up they will smash windows and spray paint walls, because they are following the desires of their hearts. For instance, Starbucks has donated millions of dollars for certain causes, but in November 2016, some of their shops ended up vandalized by the same people who were marching to support those same causes. This in my opinion is a perfect example of the heart being wicked and deceitful.
According to the gospel of Mark, Jesus said, "That which cometh out of the man, that defileth the man. For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders, thefts, covetousness, wickedness, deceit, lasciviousness, an evil eye, blasphemy, pride, foolishness: all these things come from within, and defile the man."
As you can see, Jesus basically said that you can't always trust your own heart, and reinforced what was spoken by the prophet Jeremiah.
You said, "So if you are still asking "what is God", just look inside yourself - the kingdom of God awaits you."
What will a career criminal, who's way of life is to commit robbery or burglary, find when he or she looks inside of themselves? Will their own heart challenge such a lifestyle, or justify it? What if the criminal is living comfortably from this lifestyle and has no reason to stop? What will their heart say to them? Will they find God?
Suppose a proud millionaire running a Ponzi scheme, who is not only an atheist, but someone who routinely mocks the idea of God, seeks answers from within himself. What will he find? Will God reveal himself and tell this person that ponzi schemes are bad? Or will this person, by looking within, simply discover more ways to deceive other people and enrich himself?
You sighted the account of Moses and the burning bush. Moses had an encounter with the God of Abraham, Isaac, and Jacob. When Moses asked by what name God should be referred to, the answer received was I AM THAT I AM. As the biblical account moves forward, this is the same I AM THAT I AM who speaks to Jeremiah and says that the heart is wicked and deceives.
We are both in agreement that God is very real. But I don't agree that people will find God if they look within themselves.
"For My thoughts are not your thoughts, Nor are your ways My ways," declares the LORD. (Isaiah 55:8)