We can say that his international football career is over, he may still play after serving his sentence but perhaps we will no longer see him playing for the French national team and also playing for one of the big clubs in Europe, not only because his performances will no longer be impressive but his frequent injuries would prevent any elite club from making him a player.
Even without doping, his career is nearly over and the last season is a signal for his career ending. Ending in both Juventus and French national teams as it is impossible to be called for a national team without good performances at his club. The issue with Pogba is more challenging when France has many talented players in this generation and there are many younger players who can take over a position of Pogba and replace him successfully.
You are right, it seems that every season Juventus faces a lot of problems, bad management and now their players are exposed to doping cases, but we also see that they can always get out of the problem.
Doping is not kind of regulatory attack against Juventus. It is randomly and regularly tests to make sure athletics, players and clubs don't violate doping rules and keep up fairness in league competition. It is also officially protection for players too as doping potentially causes some adverse effects on those players years after their retirements.
I don't see the drama of Pogba and his doping confirmation will be so serious for Juventus as they already accept the fact that Pogba is no longer a useful player for their squad.