By 2025, Stuttgart had agreed terms with the player, and the two clubs had settled on a transfer fee of 20 million euros, with all details confirmed in writing. Konstantelias bid farewell to his teammates at the club's training camp in the Netherlands and travelled to the airport. The transfer collapsed at the last minute, however, when PAOK's Russian owner, Ivan Savvidis, abruptly called it off, reportedly fearing a backlash from angry supporters. During this period, some fans drove to the club's headquarters and threatened staff.
Ultimately, Konstantelias extended his contract, then valid until 2027, to 2029. "In this case, things didn't always go the way they usually do," said Stuttgart sporting director Fabian Wohlgemuth after the deal fell through.
Although PAOK finished last season in a disappointing third place, Konstantelias still impressed, scoring 14 goals and providing nine assists. The club's hierarchy is now said to be determined to sell him, yet this time the player is hesitating: with his first child due in August, he is reportedly keen to stay in Thessaloniki.