The Gospel is actually this:
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. John 3:16
Preaching hellfire and damnation to the lost as the Gospel is in error.
Yes, they should understand sin and it's consequences but God is about Salvation, not Damnation.
The gospel presentation does not begin with:
“God loves you and has a wonderful plan for your life.”
It begins with:
“For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who by their unrighteousness suppress the truth.”
-Romans 1:18
You have sinned against a holy God. You stand condemned under His righteous judgment. You cannot save yourself, and apart from Christ, you will face His wrath for eternity.
That is the bad news.
And you need to hear the bad news before you can understand the good news.
The gospel is not that God has a better life waiting for you.
The gospel is that Christ came to save sinners from the wrath they rightly deserve.
He lived the righteous life you could never live.
He died the death you deserved to die.
He bore the wrath of God in the place of His people.
He rose from the grave.
And everyone who repents and believes in Him is justified, forgiven, and reconciled to God.
Don’t soften the bad news and you won’t have to dilute the good news.
The glory of grace shines brightest against the darkness of our sin.