Research.com, a leading academic platform for researchers, has just finished releasing the 2023 rankings of best scientists and universities in the world across all major scientific disciplines.
Aristotle University of Thessaloniki was ranked 2nd in Greece and 361 internationally in the 2023 rankings:
https://research.com/university/aristotle-university-of-thessaloniki
The Department of Informatics at AUTH ranked much better: 1st in Greece and 190 internationally, see: https://research.com/university-rankings/computer-science/gr
Leading scientists in the area of Computer Science in Greece can be found in: https://research.com/scientists-rankings/computer-science/gr.