Tzengko received Greek citizenship on 22 June 2018.[12][13] In 2021, she started studying at School of Physical Education and Sports Science of the Aristotle University of Thessaloniki.[3]
The following year in May, she set the world U18 best of 65.90 m (javelin 500 g) at the Panhellenic School Championships in Ioannina.[15]
On 1 August 2020, the 17-year-old threw world U20 record of 63.96 m at the Greek U20 Championships held also in Ioannina.[16] However, World Athletics refused to recognize it as a record because doping control was not conducted immediately following the completion of the competition as required by anti-doping regulations.[17]
On 20 August 2022, still only 19, Tzengko won the gold medal with a personal best of 65.81 metres at the European Championships held in Munich.[20][21] She became the youngest athlete in her discipline – male or female – to win the title at the Europeans, the first teenager to win a European throwing title, and the youngest ever Greek European champion.[22][5] In October, Tzengko also became the first Greek athlete in history to receive European Athletics Rising Star award as she was crowned 2022 Female Rising Star.[23]
^Karamitrou, Mina (2022-08-21). "Μεσημεριανό Δελτίο Ειδήσεων 21 Αυγούστου 2022" [At Noon News on 21 August 2022]. tvopen.gr (in Greek). Open TV. Archived from the original on 2022-08-25. Live broadcast from Nea Kallikrateia with Elina Tzengko's sister Isabella saying: "My sister training in miserable inappropriate facilities…"