The Oreimo manga went from 2008 to 2021, therefore the anime obviously skipped out on a major part of the story. However, this does not imply that the Oreimo anime is a waste of time.
Even though it can be strange at times, there is an enticement to the way Ryosuke and Kirino were able to patch up their broken sibling relationship.
The Oreimo anime has been out of production since 2013, yet it made a strong legacy on modern anime such as Oshi No Ko. Those who would like to give it a shot, then you can watch this series on Hulu.
The basic idea of the Oreimo anime is pretty straightforward: two siblings who are at odds and don't communicate with one another, but things change when the older brother discovers that her sister is an otaku.
An older brother named Kyosuke Kosaka doesn't appear to give a damn about her sister Kirino.
He discovers an eroge in Kirino's room and learns that it belongs to her, which surprise him. However, as time passes, he learns a lot more about her sister.
Kirino is an otaku who also works as a model. As a result, Kyosuke realizes he has no bond with his younger sister and chooses to be a bit of an older brother to her.
This is how the anime Oreimo's events happen. The plot highlights the differences between Kirino's aggressiveness and bold nature and Kyosuke's quiet and introverted nature.