Heroine—White pawn to be promoted into a White Queen.
What happens from chapter 18 on can essentially be seen as one giant game of chess as in from the book Through the Looking Glass. MC is the pawn, who promotes to Queen. She goes through the Looking Glass by rejecting the fantasy frozen world in order to get into another reality: one where she never existed in the first place. Here we can see how the guys would've been then...and it's not good. Those are the black pieces, whereas MC is a white pawn and she must continue to cross the board to become a queen, as an antithesis as to the black-wearing version of her, the black Queen. To access the Black Cabin again as well, it is mentioned that she needs to refind her identity as the Queen. This happening at the very last moment before the launch refers that pawns usually don't make it to the end of the game. However, it's far from the first time a white pawn becomes a queen after traveling through a world of 'black pieces' in a metaphorical chess game in a story.
Chapters 19 to 21 deconstruct the concept of fix fics and another parts the fandom tends to latch upon, such as mundane day AUs where nothing of the plot happened. It has always been a game where each chapter focuses on another character, but here you can choose between four routes (although they always link back to one ending). It shows a 'perfect', frozen world the main character constructed very much akin to a fix-it fic, and then makes you realize that this is fantasy, not reality, and that it is better to accept harsh reality than flee in fantasy.
There is a lot of symbolism, both on biblical fronts and on scientific front.
First of, the title "MLQC", can be a shorthand for "Modified Loop Quantum Cosmology". It turns out alternate timelines are a thing, and that the protagonist has a big hand in these, without being aware of it herself.
And then further, the literal translation of the Chinese title, 'Love and Producer', can be turned around and read as 'Evol DNA Producer', which implies that the protagonist can stimulate Evol powers.
A lot of recurring motifs are woven into the dream sequences and the story itself, such as butterflies for Lucien, stars for Kiro, time/clocks for Victor, and ginkgo biloba leaves for Gavin.
In the later chapters, Lucien and the protagonist frequently quote from 1 Corinthians 13, but not from the 'Love Anthem'.
On a much smaller scale, the song the protagonist listens to during the Doomsday Date (which is full of Foreshadowing in itself), aptly describes the date itself. The song is a Christian song written by Audrey Assad, and refers to a Biblical passage where God speaks to Elijah in the silence while being surrounded by a storm. Victor and MC eventually get into a supernatural storm, as a reflection of the past.
Insert Song: It is not actually heard, but the lyrics of the song the main character listens to during the Doomsday Date imply it's You Speak. This is a strange thing, since it is very much a Christian song (although the overtly Christian lyrics are not mentioned, just the first verse) yet it is not out of place because of the point mentioned above.
is also mentioned at the very start.