Ahead of 2020, it was announced that Olivieri would step up to WSK-organized championships.[5] In his first full year in WSK championships, he finished seventh in the WSK Open Cup and eighth in the 25th edition of Trofeo Ayrton Senna.
Stepping up to OKJ for 2022, Olivieri had a difficult year, but won the WSK Final Cup towards the end of the year.[8] Moving to OK in 2023, Olivieri finished fifth in the South Garda Winter Cup and eighth in the WSK Champions Cup before joining Birel ART ahead of the final round of the Champions of the Future series.[9]
Near the end of his karting career, Olivieri attended the Ferrari Driver Academy scout camp and the Richard Mille Young Talent Academy shootout, while also winning the 20° Supercorso Federale after impressing in the FDA scout camp.[10][11][1]
In Italian F4, Olivieri capitalised on post-race penalties to score points in the first two races at Imola and the first Vallelunga race.[16][17][18] After not scoring points at Mugello, Olivieri stayed out of trouble in a wet-dry race three at Paul Ricard to take sixth place.[19] He ended the season 17th in the standings on 11 points.
Competing in the Italian rounds of the Euro 4 Championship, Olivieri finished seventh in the second Monza race, but he would be relegated to 17th post-race after being given a 25-second penalty for contact with Davide Larini.[20] In the following race, he finished tenth on track but would be promoted to ninth after post-race penalties.[21] Olivieri finished 19th in the standings with two points.
In the first qualifying session of the season at Yas Marina, Olivieri took his first pole in Formula 4 ahead of Alex Powell.[24] In race one, Olivieri took advantage of Powell's car hitting trouble to lead all laps en route to his maiden win in the championship.[25] From 10th on the grid in race two, Olivieri climbed up to third, narrowly missing out on second as Kean Nakamura-Berta held him off.[26] Starting second for race three, Olivieri took the lead at the start after Powell stalled from pole and held off Nakamura-Berta to take his second win of the season by 0.071 seconds.[27]
