Time Travel in Star Trek: Lower Decks (LOW)
"And to think, you go to bed, probably still thinking about some task you have to do the next day, then poof. You're gone." (Boimler, LOW: "Crisis Point 2: Paradoxus")
LOW: Crisis Point 2: Paradoxus
The first time travel story in Star Trek: Lower Decks is just a holographic scenario. It involves a device called Chronogami that Boimler most likely made up for the simualtion and that doesn't exist in-universe. "'Chrono' because it involves taking time, and folding it on itself like the Japanese art form [of origami]", as the holographic Freeman explains. The Chronogami works with gravitons that fold world lines, which usually run from the beginning of time to the end, in a way that they intersect. It hence allows a user to travel to any point in the future or in the past and change history. This principle does not differ much from "real" time travel technology previously seen in Star Trek. Actually devices such as the Klingon time travel crystals from Boreth as in DIS and SNW appear to be more powerful.
In Boimler's story, the Romulans led by the Melponar Triplets steal the Chronogami and attempt to wipe the Federation out of existence. The Starfleet crew receives a tracker from Dr. Gibson and chase the Romulans through time. They travel to the year 2341, when the algae crisis might have destroyed the Federation if it had not been for Ambassador Koro. The next stop is Sydney in the year 1982 where an ancestor of Koro was apparently held in an aquarium. The Romulans then proceed to the year 2161 and plant a bomb in the assembly hall where the Federation is founded. The part about Koro does not have to be historically accurate considering that Boimler created the program for entertainment in the first place.
The team led by Tendi finds the bomb in 2161 and Rutherford successfully defuses it. So far no change to the timeline has taken place. This is why the team can return to the very instant the Romulans steal the device. So far, so good. Yet, a problem occurs because the Starfleet crew (real as well as holographic) is aware of what has happened in the meantime and can outsmart the Romulans by swapping out the Chronogami for the bomb. Unlike the Romulans, the consciousnesses of the Starfleet crew seem to have traveled into their own bodies at that time. Perhaps we should accept this as a deliberate twist in the holographic scenario that would not work in the "real" world.
Classification: attempted past incursion (simulated only)
SNW: Those Old Scientists
See Time Travel in Star Trek: Strange New Worlds.
LOW: Fully Dilated
Mariner, Tendi and T'Lyn are going to beam down to the planet Dilmer III. Rutherford and Boimler tell them that "the planet's core has created a space-time differential" and that "for every second on the Cerritos one week is gonna pass for you on the surface". This is a very similar situation as in VOY: "Blink of an Eye", as Tendi recognizes.
The originally planned duration of the mission is not mentioned any more precisely than in Boimler's statement that they will be gone for "like a second". It is possible that a timer was set to activate the beacon that T'Lyn is carrying (so they can proceed to a safe place for beam-up) and then initiate the transport like 100 milliseconds later (because why would they need to wait another week)?
Anyway, whatever the original plan was, due to Boimler spilling his ostentatious drink on the transporter console, the three spend as long as ten months on Dilmer III, while Rutherford and Boimler are struggling to clean the surface. They eventually press both buttons for the beacon and for the transport manually (which wastes another couple of weeks on the planet).
The story inherits all the fundamental problems of visualizing different time levels from classics such as TOS: "Wink of an Eye" or TNG: "Timescape". It disregards the frequency shifts of incoming and outgoing light. Also, unlike in VOY: "Blink of an Eye" the planet Dilmer III is perfectly round and is not spinning as fast as it should to provide a reasonable day/night cycle.
Classification: different time levels
LOW: Fissure Quest
As the Beagle of Captain Lily Sloane travels to other dimensions, it obviously also travels through time. The ship has to be from Earth's 21st century and arrives in the 24th century. It is yet unknown whether they will be able to return to their time, or only to their universe. Other interdimensional travels of the season don't involve time travel for all we can tell.
Classification: time travel to the future