Moses doesn’t die in the book of Exodus(second book of the Pentateuch) he dies in Deuteronomy (the last book but it goes on after he died). The decalog is what is said to have been contained on the tablets that were given to Moses by God, yes. Again, Muhammad didn’t make that up. The original tablets were not “lost” either they were smashed by Moses himself according Christian and Jewish bibles in Exodus 32:19. Then Moses chiseled out the decalog himself again later (Exodus 34.) the decalog is in 2 different places in Jewish and Christian bibles (both Exodus and Deuteronomy) and they quite frankly don’t match each other. I don’t know any abrahamic faith who doesn’t think that Moses destroyed the tablets but they were just lost instead. Pretty sure they all agree that Moses smashed them on purpose.