There's no cause for alarm in Ligue 1 because even if these two players are absent throughout this season, PSG will definitely win the title again. In UCL, it will definitely affect the team performance because they will be playing with teams with the same qualities with theirs. I am not expecting much from PSG this season though.
If they give their full effort in Ligue 1, winning the Ligue 1 title is not a difficult task for PSG. But the problem is that PSG will try to win the Champions League title this season as well. And the most important thing is that most of PSG's opponents in the first round of the Champions League are very strong. Atalanta, Bayern Munich, Tottenham, Leverkusen, Sporting, Barcelona and Newcastle, which team will we call weak? Every team is very strong. No other team will face such a strong opponent in all matches. So getting through the first round is now a big challenge for PSG. So I will not be surprised at all if I see irregular performance from PSG in Ligue 1 matches.