Transhumanism is an atheist religion.
I don't think it inherently is either atheistic nor a religion although obviously could be treated as such in some form.
And one certainly doesn't have to be a materialist to think science will figure out ways modifying what it means to die or end the limits of the 120 year current human genetic lifespan.
Computers are capable of being more intelligent than humans in many ways - they simply lack a conscious structure.
We both believe that spark is a connection to a soul. I wonder though why do you think a soul couldn't join a computer? If I replaced my biological body 99% machines - you think that 1% remaining contains some special sauce? of course not, it's just a vessel.
We spiritualist already believe we are transhuman. The only question then is time scale(then/now vs when), an illusion of space and location via movement.
Transhumanism could be the religion of the progressive elites who are working on forming a global government. Run by them, of course. The rest of us are too stupid to understand any of it.
Industrialists/government can not contain what is coming. Enthorphy break any control over any degree of time. Even a matix-esk simulation would be broken with time. If you live to the next tipping point, you will simply witness the small g gods. Just as you ancestors witnessed powerful new technologies and seemingly insurmountable and personal natural forces before and called them by the same name.
What was once the hard limit of what is possible. Can be broken. This is most often conveyed in the story of the 4 min mile.
1. Science still doesn't know what life is.
Nor does it try.
2. Science still doesn't know how the brain works.
Consciousness is not in the brain, but it is a pattern. A pattern can be repeated and abstracted.
3. Science still doesn't understand most DNA.
It is a way of encoding data and expressing it. What more does one need to know past that? What you describe is not a scientific problem its an engineering problem.
4. Science is no closer to curing cancer than it was decades ago.
Cancer like death is naturally occurring and exists due to the mechanism of imperfection in the unfoldment of life. This mechanism is a critical difference between biological and artificial. In the same way, water and distilled water can be the same yet different.
In a healthy biological system these transcription errors due to deterioration or outside influences get corrected. Junk DNA is one such natural protection for example. Telomeres then are directly tied to the leading cause of cancer. Cancer afterall is a process more than any one specific error.
So again its not a not a scientific problem its an engineering problem. Even if one didn't perfectly understand cause or method of the DNA error what is missing is more a way to apply any method of artificial correction. There currently only exists indirect ways. A matter of technological improvement specifically nano-technologies and more bio-friendly materials and controls. That is not a question that is stalled in its progress.
5. The causes of most age-related diseases are still unknown.
But you get exponential return. So for example with the aforementioned telomeres for example. A deterioration processed solved in your reproductive cells with known enzyme telomerase. Let say we had a deployment method which through keeping DNA full doubled the current best results of restricted calories diets. That may expand the average human lifespan to say 180, limit of 240 and boost mental age of research say to 21-160. That little extension increases the likelihood of the next step by factors. So on and so forth.
I wouldn't take transhumanism lightly. Nor think it some type of false hope.