It may well be that really to want Heaven, to prefer Heaven (as it actually is) to any other possible outcome of biological death; may be sufficient for salvation - at least in these end times.
Certainly, it seems to be very rare for people to want resurrection, to want to dwell eternally in a situation with God the creator, Jesus Christ, and others who have made this choice; to live as sons and daughters of God and to join in the creation of creation.
So many people seem actively to desire extinction at death (not to have eternal life); or to live on a spirits (not be resurrected), or to cease to exist as separate selves (not to become sons and daughters of God); or if resurrected to live in a paradise of rest and peace, or passively enjoyment of sensuous pleasure...
If any of these (or other alternatives) are wanted instead of Heaven - I cannot see any possibility that such a person would follow Jesus to attain what Jesus offers.
Jesus would not be offering any-thing such a person wanted. Conversion would have no point, offer no benefit - and would not happen.
But if someone wants to live eternally by being resurrected in Heaven - if that is his post-mortal desire; then it may not matter very much whether - in this earthly life - he believes that Heaven is possible, and real.
It may not matter much even if he thinks Heaven is nothing more than wishful-thinking...
The facts, the realities, will be discovered after death. Then he will know what is possible.
And once the hope of Heaven becomes both a reality and a possibility - presumably such a soul would gratefully accept the great gift; and would choose to follow Jesus.
Therefore; perhaps the most valuable discussion a Christian evangelist could have with a convinced materialist-atheist would be concerned with what he would most like to happen after death; and an exploration of the various possibilities 'offered' by atheism and various religions. Leaving aside which is true and real - a simple discussion of what is most desired.
Someone who has their own greatest wish clear in mind may find that this is exactly what Jesus offers; and may then take further steps.
But without prompting, few will make the effort even to think about post-mortal life; and will be too paralyzed by the dishonest assumptions of pseudo-realism of mainstream materialism, even to think-through what has been said on the subject - through history and around the world.
In sum; explicit fantasy and imagination concerning life beyond biological death may be the greatest ally in moving someone towards ultimate salvation; with the world as it is now.