[2] In 2020, following the withdrawal of Alexandre Cougnaud and a positive test at the end of the 2020 Castellet 240 with Graff Racing, Milesi had the opportunity to join this same team in order to participate in the 24 Hours of Le Mans in the hands of an Oreca 07 in the LMP2 category with Vincent Capillaire and James Allen as co-drivers.

With this first experience in the hands of an LMP2 and following the withdrawal of the Mexican driver Memo Rojas,[5] Milesi had the opportunity to join the American team DragonSpeed in order to participate in the 4 Hours of Monza.

[7] Milesi then finished his year by taking part in the final of the Michelin Le Mans Cup with the CD Sport team in the hands of a Ligier JS P320.

[10] That year, the Frenchman's main campaign would lie in the FIA World Endurance Championship, where he partnered Robin Frijns and Ferdinand Habsburg at newcomers Team WRT.

[12][13] Encouraged by the result, the outfit performed strongly during the 24 Hours of Le Mans, leading into Sunday afternoon before encountering issues that meant that the sister WRT car looked to be on course to win the race.

[19] The following year, Milesi would remain in the WEC, moving to the Richard Mille Racing Team to drive alongside Lilou Wadoux and Sébastien Ogier.

[22] The Frenchman showed his pace by setting the fastest race lap on four occasions, as the lineup overcame a slow start to the season by finishing fourth at Le Mans and second in Monza, leaving the team seventh in the LMP2 standings.