So first of all, I believe that St. Katherine of Alexandria's hagiographies are the personification of the mythical Library, especially because her monastery now boasts the largest collection of ancient papyrus and codices ever assembled. It is rather clear to me that the Sinai monastery is the actual successor, and that the vast majority of Alexandria's collection never burned at all. (The monastery also hosts Moses' burning bush and famously, a fire extinguisher is mounted next to it.) Muhammad himself ordered the sparing of the community during seige times.

That being said, I also believe that the ancients were well-aware that our Sun is a local star. And by extension, that stars are distant suns. I have been doing research on the Star of Bethlehem, and it is painfully, obviously clear that the Star sought by the Magi is the Sun itself, since when they met with Herod, they first described Springtime (late April through June) and then the Winter Solstice as they pursued the Sun to Bethlehem. Furthermore, anyone traveling for seven months, and only at night, in the ancient world, while bearing priceless treasures, would have been fools, unless they also carried torches, weapons, mercenaries, and medical supplies. Furthermore, any Hellenistic pagan reading the New Testament would've clearly discerned the identification of Jesus with the divine aspects of Phoebus Apollo (among other Olympians); the Sun metaphors continue to the present day. The Star of Bethlehem simply cannot be distant, dim, or anything but our own Sol.

Anyway, yeah, recently the descriptions of the large-scale copying at the Port of Alexandria has convinced me that the Library amassed a gigantic collection of knowledge and texts, and those were, for the most part, safely transferred "by angels" to Sinai when the time was right. And palimpsests notwithstanding, there are still tons of texts still unread, unindexed, and undiscovered in there.