She lifted a chunk of an ocean, not the entire ocean. Erasing the whole surface of a planet is far above what Psykos pulled off. Moreover, you realize she's having trouble with Tatsumaki right ? Stop getting excited over this feat, Boros is the undisputed strongest along with AG, the actual final boss of this arc, who crushes Tatsumaki, and whom Boros is directly compared to. You can try to spin it any way you want lmfao.
Though, i might concede he can't solo the association, depends on how GS is gonna stack up to Psykorochi. Rest don't matter.