She is also a good talent, but didn't improve this year which is very worrying at this age + the greek girl beat her yesterday despite clearly having worse wind.
Don't get your point here. What exactly do you mean with reliable? Of course talents that are producing eye-catching performances at such a young age are more likely to be successful at senior level.
Of course most of the medallists here will never win a medal at senior level, statistically speaking there is a good chance that 6 or 7 medallists will win medals at senior world championships/olympic games in the future. At the same time statistically speaking there is a good chance that 11 or 12 medallists from the U23 european championships will go on to win medals at senior world championships/olympic games, so in general the results at U23 european championships are a better indicator of future success (obviously, since the talents there are closer to senior level age-wise). As far as i know Lewandowski never won a medal at senior world championships/olympic games, so he isn't even included in my statistics, but here are some examples of athletes who won medals at U20 and U23 european championships and then went on to win medals at senior world championships/olympic games:
U20: Hejnova, Ennis, Kszczot, Shubenkov, Spanovic, Thiam, Schippers, Perkovic, Mayer, Lasitskene, Kolak, Warholm, Rutherford
U23: Hejnova, Ennis, Kszczot, Shubenkov, Spanovic, Thiam, Schippers, Stahl, Storl, Fajdek, Stefanidi, Röhler, Gudzius, Farah, Klüft, Harting, Mekhissi