[6] After graduating, he started attending the Nippon Sport Science University in 2020 and reached fifth place at the Emperor's Cup that year in the 61 kilogram class.

[10][11] Competing outside Japan for the first time in his career, Kiyooka won the championship at the Dan Kolov & Nikola Petrov Tournament, defeating returning champion Islam Dudaev, Olympian Agustín Destribats and U23 World finalist Mikyay Naim.

[2] At the qualifier, he defeated U23 European finalist Abdulmazhid Kudiev, Olympian Yun Jun-sik and Yuan Shaohua to reach the Olympic quota.

[15] In June, Kiyooka entered the Polyák Imre & Varga János Memorial Tournament, where after a first-round loss to three-time World champion Haji Aliyev, he rebounded with victories over reigning World champion Ismail Musukaev, NCAA finalist and fellow Olympian Austin Gomez, and Abbas Ebrahimzade, winning gold.

[17] On the first day, he opened up with a technical fall over Maxim Saculțan from Moldova, followed by hard-fought victories over returning World finalist Sebastian Rivera from Puerto Rico and Asian Games champion Tömör-Ochiryn Tulga from Mongolia, cruising to the finals and securing a medal.