This multiverse storyline allowed Star Trek: Lower Decks to bring back several characters from various Star Trek shows and eras. The vastness of Star Trek's multiverse allows for an infinite number of possible realities, meaning characters from any timeline could appear, and even return from the dead. Multiverse stories have become popular in modern media like the Marvel Cinematic Universe, but Star Trek has explored parallel universes since Star Trek: The Original Series. Star Trek: The Next Generation took things even further, exploring the exact same phenomena the USS Cerritos encounters in Star Trek: Lower Decks season 5.
Star Trek: The Next Generation Season 7 Introduced Lower Decks' Quantum Fissure Multiverse Problem
Lt. Worf Encounters A Quantum Fissure In The TNG Season 7 Episode, "Parallels"
In Star Trek: The Next Generation season 7, episode 11, "Parallels," Lt. Worf (Michael Dorn) returns from a Bat'leth tournament and soon begins noticing changes on the USS Enterprise-D. As the changes become more and more significant, the crew of an alternate reality Enterprise determines that Worf encountered a “quantum fissure in the space-time continuum," causing him to shift between various quantum realities. At the end of "Parallels," hundreds of Enterprise-Ds start appearing through various quantum fissures, and the Enterprise crew must find the one from which Worf originated.
"Parallels" makes great use of the concepts of quantum fissures and parallel universes bleeding over into one another in only a single episode, but Star Trek: Lower Decks season 5 expands on the idea. Stretching the idea over a whole season allowed Lower Decks to explore Star Trek characters from alternate realities and touch upon "What if" scenarios from Trek lore. "Parallels" is a great episode of TNG, and I'm glad Lower Decks found a way to revive the concept of quantum realities in a really fun way.