You've made that quite clear. You don't believe that all recipients of eternal life shall never perish.
See here is the problem.
This is a many layered issue here.
All who have gained eternal life have not perished.
But one is only eternal if the Lord maintains ones life eternally and ones name is in the Lambs book of life.
Heb 6:4-6 paints the possibility of those who are 100% of the faith, yet fall away, are lost.
So two statements can be made that are true because they are talking about different groups. To avoid certain meanings of being a sheep from birth, ie predestined to eternity or predestined to judgement, people say goats, pigs and dogs turn into sheep.
But as an analogy, this is impossible.
Jesus talks about different flocks of sheep, sheep of Israel, and of others which is more relevant.
I have other sheep that are not of this sheep pen. I must bring them also. They too will listen to my voice, and there shall be one flock and one shepherd.
Matt 10:16
Goats do not become sheep, it is the sheep who hear Jesus's voice.
But sheep can be lost, and not found, wander off and die.
As Jesus says if the sheep is found and restored
I tell you that in the same way there will be more rejoicing in heaven over one sinner who repents than over ninety-nine righteous persons who do not need to repent.
Luke 15:7
People will always want to excuse sin and claim spiritual reality and its eternal nature, but then deny it by saying believers can go back to the world as if this does not matter.
Equally there are some who appear to be goats, wolves, pigs, dogs in their behaviour and intent. If everything is fluid, then who is of the faith and who is not, God could just make us all righteous, pure holy people against our will, and no one in hell. This is how absurd people get. And it is a form of universalism, claiming it is all in Gods hands and evil and sin can just be cleaned up, like cleaning a house, so no problems folks, its all just a bad dream.
The problem here is mixing Gods gift of life with our own internal struggles, and not admitting we both need to understand ourselves, our struggles and bend the knee in repentance and faith and literally follow Him. Without the following we are just empty sinners with a pipe dream.