It's his biggest club ever managed as a head coach and he lacks experience for it, as well as there is much big pressure on him. Remember that in his first position with Bologna, that club did not perform too well but in a second position with them, Thiago Motta brought them to top four and Champions League. Give him some time and let's wait for his management in Juventus next season.
In terms of experience, Thiago Motta's ability is not yet proven, but his success when managing the team before Juventus can be said to be quite successful. Now it takes patience for the fans towards him and maybe it takes adaptation that must be adjusted so that Juventus can be better in the future. It doesn't look easy but if he is given time, maybe there will be much better results that Juventus will get, besides that they also need to recruit some additional players to make the strength stronger. Changing a club to be better in a short time is impossible because it takes balance in terms of adaptation, team cohesion and the way the coach makes a suitable strategy so it takes time for that.