It sounds quite distopic to hint that a treatment for being afraid of death is enough drugs to make you believe in an afterlife.
Check out the 2022 study "Comparison of psychedelic and near-death or other non-ordinary experiences in changing attitudes about death and dying"
https://journals.plos.org/plosone/article?id=10.1371/journal...
Specifically Table 7, which shows changes in attitudes of psychedelic vs non-drug (who had non-drug near-death or other non-ordinary experiences) participants.
It shows changes of certain attitudes towards death between these two groups. There is a large positive change in curiosity about death. The increase in the attitude you mention, the Approach acceptance ("I look forward to life after death") was actually increased more in the non-drug participants who underwent NDE or similar, as compared with psychedelic participants. But a far larger effect in the decrease of avoidance attitudes ("I avoid death thoughts at all costs"), and an even larger effect in simply having a reduced fear of death.
From this, and from personal psychedelic experience, I do not think increased belief in an afterlife is the primary driver of a reduced fear of death following psychedelic experience. I think the attitude change has much more to do with gaining universal acceptance of death as a natural consequence of life.