Yamaguchi qualified for the floor exercise final at the 2021 All-Japan Event Championships and finished in seventh place.

[4] She then finished eighth all-around at the 2022 NHK Cup, and she had the highest scores of the event on both the balance beam and floor exercise.

[6] She helped her club finish in fourth place at the 2022 All-Japan Team Championships, and she won the all-around bronze medal behind Shoko Miyata and Mana Okamura.

The Japanese team of Yamaguchi, Mika Mizuno, and Haruka Nakamura won the gold medal by over two points ahead of the United States.

[11] Yamaguchi was in the lead after the first day of the 2023 All-Japan Championships with a total score of 54.566, almost a full point ahead of World champion Watanabe Hazuki.