Loan to Cuneo and Rende

On 16 August 2018, Borello was signed by Serie C side Cuneo on a season-long loan deal.^[2] On 17 September he made his Serie C debut for Cuneo in a 1–0 away defeat against Pisa, he was replaced by Giorgio Spizzichino in the 78th minute.^[3] Three week later, on 14 October, he scored his first professional goal in the 43rd minute of a 1–0 home win over Olbia.^[4] On 25 November he scored his second goal, as a substitute, in the 86th minute of a 3–0 away win over Alessandria.^[5] In January 2019, Borello was returned to Crotone leaving Cuneo with 15 appearances, 2 goals and 1 assist, but he never played any entire match.^[6]

On 8 January 2019, Borello was loaned to Serie C club Rende on a 6-month loan deal.^[7] On 20 January he made his debut for Rende in a 3–0 away defeat against Catanzaro, he played the entire match.^[8] Three days later he scored his first goal for the team in the 46th minute of a 4–2 home defeat against Monopoli.^[9] He became Rende's first-choice in the second part of the season. On 28 April he scored twice in a 3–1 away win over Viterbese Castrense.^[10] Borello ended his 6-month loan to Rende with 17 appearances, including 16 as a starter, 3 goals and 2 assists.^[6]

Loan to Cesena

On 18 July 2019, Borello was loaned to newly Serie C side Cesena on a season-long loan deal.^[11] Five weeks later, on 25 August, Borello made his debut and he scored his first goal for the club in the 43rd minute of a 4–1 away defeat against Carpi, he played the entire match.^[12] He became Cesena's first-choice early in the season. On 15 September he scored his second goal in the 66th minute of a 3–2 home win over Triestina.^[13] Four more weeks later, on 13 October, he scored his third goal in the 62nd minute of a 3–1 home defeat against Sambenedettese.^[14] Borello ended his loan to Cesena with 26 appearances, including 22 as a starter, 6 goals and 1 assist.^[6]

Loan to Pro Vercelli and Cesena

He appeared on the bench for Crotone on 3 October 2020 in a 2020–21 Serie A game against Sassuolo. On 5 October 2020 he moved on loan to Serie C club Pro Vercelli, becoming the fifth Crotone player loaned to Pro Vercelli for that season.^[15] Six days later, on 11 October, he made his debut for the club as a substitute replacing Alessio Zerbin for the last 15 minutes of a 2–1 home win over Lucchese.^[16] On 11 November, Borello played his first match as a starter for the club, a 1–0 home win over Pistoiese, he was replaced by Alessandro Romairone in the 71st minute.^[17] However in January 2021 his loan was terminated and he returned to Crotone leaving Pro Vercelli with 11 appearances, including only 3 of them as a starter and without playing any entire match for the club.^[6]

On 15 January 2021, Borello returned on another loan to Serie C club Cesena until the end of the season.^[18] On the next day he made his debut for Cesena as a substitute replacing Mattia Bortolussi in the 89th minute of a 2–0 away win over Arezzo.^[19] Two weeks later, on 30 January, Borello played his first entire match for the club in a 2–1 away defeat against Triestina.^[20] Borello ended his 6-months loan to Cesena with only 9 appearances, he also helped the club to reach the play-off but Cesena was eliminated by Matelica in the second round.^[6]