[3] On 12 January 2022, Cortés made his debut for Millonarios' first team in the opening match of the Apertura against Deportivo Pasto.

[5] On 12 May, he scored his first professional goal in a second-leg Copa Colombia match against Jaguares de Córdoba, contributing to Millonarios' 1–1 tie in the game and aiding the team in advancing to the quarter-finals 4–1 on aggregate.

[6] After an impressive performance for Colombia at the 2023 South American U-20 Championship, Cortés drew the attention of Serie A club Torino, who have been linked with a potential move for the player.

[8] On 2 March, a remarkable display by Cortés played a pivotal role in Millonarios' victory over Ecuadorian side Universidad Católica in the second round of the 2023 Copa Libertadores.

On 3 June 2024, Rangers announced that Cortés had signed another loan deal for the 2024-25 season, with an obligation to buy in the summer of 2025.