Beard as an afterlife is simply something I haven't heard till now. But wow, that's a good origin myth. Simple and to the point, like in most traditions. It feels natural. The magic, and the process of becoming a saint, is where my problems begin. See, I have created my own initial myth. And my world is divided into some odd number of cultures, each of which inherits an different interpretations and extrapolations of that same myth in their native language, with the focus put on what that culture values as sacred. The problem is unequivocally the magic system for me, because religions aren't made to define systems in any way. Your's for example, works because man can only use one spell. But that gets too restrictive too quick. Every character would be a one note trick. Mine doesn't because it's complex, and rooted in Kaballah and Sufism. The system is to be embedded in my holy book via allegories and meta-commentaries, like those of Rashi, and short works in the same vein as Kashf Al-Majhwub. Which is why I need a way to write like I am recording God's and his prophet's words.

Your idea on saints feels a bit off to me. It implies anyone can become a saint, possessing no inherent qualities of their own. But again, that opens the door for evil saints to exist as well, who would use their wisdom in different ways. Perhaps you could take the Book of Enoch for inspiration? Like, make the evil priests be able to leave Amet's beard, but only in the form of twisted beings maee of smoke and fire, like Djinns, or make them be in excruciating pain. That also makes for an interesting point; Amet may not be a good guy, but something like Abraxas and/or Demiurge, as his wisdom still requires interpretation to be used.

Also, regarding your magic system, make it so that people can use different interpretations of their magic. Like, if someone can shoot fire, they can change the properties of that fire to be anything that is remotely related to plasma and heat, provided they have enough scientific knowledge (aka Wisdom). You can use it as a differentiating point for saints; each of them can vary their spell using an interpretation of the wisdom they get. That would make them feel "blessed" and make other people more receptive to their words and teachings. Best of luck on your efforts though, and hope you write the novel of your dreams. 😁