The anime left off at a point that was somewhat mid-way through the novel series. But it varies depending on how you define the specific plot points and story arcs.
In general, the point where the Boruto anime stops compared to the manga is not straightforward. It varies due to the way the story is adapted and presented in each medium. Sometimes, the anime might take detours or add filler episodes that aren't in the manga.
The Tokyo Ghoul anime leaves off around the point where Kaneki has joined Aogiri Tree in the novel. He has started to become more involved with their activities and his character is on a path of further transformation both physically and mentally.
Well, generally, the Arifureta anime stops at a point that corresponds to a certain part in volume 3 of the light novel. There are some key events and developments in the anime that are covered up to that point in the source material. This is important because if you want to continue the story from where the anime ended, you would start from volume 3 of the light novel. It also means that there is a lot more content in the light novel that wasn't covered in the anime, such as more in - depth character backstories, additional plot twists, and further exploration of the world that Arifureta is set in.
The anime of Danmachi typically leaves off at a certain point in the light novel, but it varies depending on the season. Usually, it doesn't cover the entire story arc.
The story of Overlord left off at a significant plot point involving the main character's confrontation with a powerful enemy in the light novel.
Well, I remember that Overlord left off in the light novel at a stage where the main characters were facing some major challenges and the story was getting really intense. I'm not sure of the precise details though. You might want to check some dedicated fan forums for a more accurate answer.
The JJK anime typically leaves off at a specific chapter or arc in the manga, but it can vary depending on the production decisions. Usually, you can check official sources or fan discussions for the exact point.
The Bleach anime leaves off at a point that's roughly around the middle of the manga's story arc. But the exact chapter can vary depending on how you measure it.
I think it left off at a major plot twist involving the main character's discovery of a hidden truth about their powers.
There are fanfictions where Issei leaves to protect others. He might learn of a great danger that is coming and decides that the best way to keep his friends and loved ones safe is to remove himself from the situation. So, he leaves, hoping that the enemy will follow him instead of targeting those he cares about.