I guess i'm judging him the same way i would judge him if he were to go to PSG.
The player that was the most exciting at Monaco, for me, was Bernardo. His quality was evident and i was sure he would be a sensation for City. People like to dismiss Ligue 1 but if you are very good there, you'll be good very good everywhere. Mbappé, Fabinho are other examples. You can add former PSG player Lo Celso that went on being the sensation of the season in Liga and rumoured to be Spurs record transfer this year.
Tielemans used to do his mid range or long range shot since he has a powerful strike but would be very inefficient despite some screamers. His 5 goals stat is meaningless and don't tell the whole story.