[4] In his first three seasons, Ioannidis failed to make an impression, but in the 2023–24 he managed to solidify himself in the starting line-up, becoming a key member in Ivan Jovanović's plans.
On 21 September 2023, Ioannidis scored in a 2-0 home win against Villarreal for the opening matchday of the Europa League group stage.
[5] In the aftermath of his impressive performance, several European clubs expressed interest in Ioannidis, with Panathinaikos demanding offers higher than €10 million.
[6] Ioannidis finished the season with 23 goals and 9 assists in all competitions, which resulted in interest from numerous clubs, including Sporting and Girona.
In mid-June 2024, newly promoted Ipswich Town offered a €22.5 million record fee for his services, but his team refused to enter negotiations.