Concerning the convergence of faith
Several faiths have arisen independently on each and every sentient planet, even Kondoria and Babababa. Zero gods, one god, two gods, many gods, and I don't know. These also vary in how much the god or lack of god matters. Some monotheists think their god created the universe but doesn't really intervene in people's lives. Some think their god intervenes and loves them. Very few people believe in a god that hates them, quite possibly because natural selection of memes would work against that belief.
The most popular faiths are atheism, agnosticism, Savior worship, deism, Walkers of the Oneness, ditheism, spiritualism, and polytheism.
Walkers of the Oneness does not fit the traditional mold of "how many gods and how much do they care" but is still very much a faith. They believe that there is not so much difference between "one" and "all." They explore the relationship between the individuality of creatures in the universe and the fact that all individuals exert an influence on all other individuals. So is there really more than one of anything if the whole of everything acts as one moving part? I can't really articulate the view well, but I believe it develops on every planet because there really is something important about the relationship between the part and the whole.
Atheism, agnosticism, and deism are all simple to explain; no god, I don't know if there's a god, there is/are god(s) but they don't care. There is a great deal of diversity within each of these groups, but the fundamental beliefs warrant little explanation.
Ditheism, sometimes called Gender Spiritualism, asserts that the universe is created by two opposing gods or forces. This became a much more popular religion once intelligent species realized that every other intelligent species also develops two sexes. Some assign genders to the two forces, some do not. Some characterize it as destructive versus creative, finite versus infinite, or light versus dark. Some mix ditheism with Oneness and believe the universe is a conflict between individual and community.
Polytheism comes in many different forms, but generally they espouse wide collections of less powerful gods. Sometimes the gods are aspects of nature, sometimes they are deceased ancestors, sometimes they are strongly held values. Polytheism generally becomes less popular as a species develops, but it generally originates as it seems to primitive creatures that many physical and ethereal objects have agency.
Spiritualism is similar to polytheism, but it is different in that individuals have spirits that can contend on level ground with the spirits of objects or ideas. This is another faith that I cannot articulate well. But it is important to note that people are not just people in this view; the organic beings are simply shells and the real person exists in the ether or something.
Savior worship is the most popular form of monotheism. It arises after a member of any given species claims to be a deity and, instead of using their position in society to gain power, chooses to become poor and eventually allows themselves to die. They are generally believed to be a god for long after they die.
The remarkable thing, and the thing that Savior worshipers are quick to point out, is that the Savior has a similar personality on each and every planet. They are kind, wise, and humble. They heal people, the teach people, and they apparently violate the laws of physics, but because the Saviors invariably come about before science is well established, it cannot be determined if they actually do manage to violate the laws of physics. They challenge the established authorities and are therefore sentenced to death. The Saviors do not seem to fear death, and legends claim that the come back to life after death but again, this is impossible to confirm.
Savior worshipers are often the most anxious to study the development of dominant species on primitive planets because they want to find an active Savior, but this has yet to happen.
The modern belief of these faithful is that there is one god that loves every intelligent species and sends himself in the form of members of each species to communicate their love.
Why do all of these religions develop independently on different planets? I assume because each of them explains something helpful about the world. Or perhaps it is because there is a god and they want every individual to be able to choose what to believe freely, and part of this free choice is for there to be multiple options.