The length of the Genshin story is hard to define precisely. It's constantly growing as the game developers introduce new quests, characters, and plotlines. But it's already quite substantial.
Well, the Barnacle Boy story is often associated with the 'SpongeBob SquarePants' universe. Barnacle Boy was a superhero sidekick. He and Mermaid Man fought crime in Bikini Bottom. They had a lot of wacky adventures, like trying to stop villains from stealing the secret formula of the Krabby Patty. Barnacle Boy was always a bit grumpy and sometimes didn't get along well with Mermaid Man, but together they were Bikini Bottom's protectors.
A barnacle gosling's life story begins with hatching from an egg. It is then under the care of its parents, learning to find food which mainly consists of small invertebrates. As it grows, it molts several times to accommodate its increasing size. It gradually becomes more independent and starts to explore wider areas in search of better feeding grounds. Eventually, it reaches maturity and may start the cycle anew by finding a mate and reproducing.
Since I'm not aware of the 'the ugly barnacle' full story, it could be about the life of a particularly unattractive barnacle. It might describe how it endures in its environment, perhaps facing challenges like competition for space on rocks from other organisms, or how it deals with changing tides and water conditions. It could also be a story with a moral lesson about not judging by appearances, if the barnacle has some unexpected positive qualities despite its ugliness.
It really depends. Some Genshin story quests are relatively short and can be done in an hour or two. But complex ones could take five or more hours to finish, depending on your gameplay speed and how much you explore the details.