Well, an all-loving God would have elected to give everyone a new heart, and on what just basis would He elect some rather than others?
Receiving a new heart comes with regeneration.
Being made able to know and understand spiritual realities.
Having a new heart is by no means meaning one can not follow errors.
It only means that one can now learn correct Biblical ways to counter the errors.
Whereas, before getting a new heart?
Nothing could have made sense one way or the other.
There would be no admonitions for the Church to stop living in errors found in the Bible if having a new heart indicated an automatic
ability to be always right in rightly handling the Word of God. Stupid Christians fail to see that.
'Stupid' is a Biblically sanctioned word...
"Whoever loves discipline loves knowledge, but he who hates correction is stupid"
Proverbs 12:1