What leads to your opinion that “conversion” does not gain “Heaven”? Is Christ now in “Heaven”? Where are the 12 apostles, including Judas Iscariot, & the apostle Paul? Where are those who died in the faith & those who “died in their sins”? What is the meaning of Luke 16:19-31? Do all go to “Heaven” at death, both those whose father is the devil & those who are born of God? Both those who do His will & those He never knew?
Here in Luke 10 Jesus does not tell the disciples to rejoice in their service in delivering people from demonic spirits, but that their names are written in the Heavens:
Yet do not rejoice in this, that the spirits are subjected to you; but rejoice that your names are written in the heavens. (Lk.10:20)
Where do we ever read of anything like that regarding the wicked? Not here:
40 And the other answering, was rebuking him, saying, “Do you not even fear God, that you are under the same judgment, 41 and we indeed justly? For we are receiving things worthy of what we did, but this man did nothing wrong.” 42 And he was saying, “Jesus, remember me when You come into Your kingdom!”
43 And He said to him, “Truly I say to you today you will be with Me in Paradise.” (Lk.23:40-43)