[1] He broke into the senior level scene in 2021, when he claimed the Russian National Championship, earned silver at the European Continental Championships and qualified to compete at the 2020 Summer Olympics by winning the World Olympic Qualification Tournament.

[6] The following year, he burst into the scene by claiming the 2021 Russian National Championship, upsetting two–time National champion and '19 European Games gold medalist from Chechnya Anzor Khizriev in the semifinals and beating Atsamaz Tebloev in the finale.

[6] Next, he competed at the 2021 European Championships, where after wins over Oleksandr Khotsianivskyi and Dániel Ligeti, he went on to lose to three–time Olympic and World Champion from Turkey Taha Akgül, who claimed his tenth European Continental Championship, claiming silver.

[7][8] Kozyrev competed at the 2021 World Olympic Qualification Tournament, and after consecutive wins over '20 Bulgarian National runner–up Georgi Ivanov, '20 Individual World Cup runner–up Robert Baran and two–time European Championship medalist Dániel Ligeti, he was able to cruise to the finals, thus qualifying for the 2020 Summer Olympics.

He won his match against '18 Commonwealth Games gold medalist from India Sumit Malik by walkover on May 7.