Indeed, it's still too early. PSG can still show their best to their fans later, right now also they gap only 2 points different with Monaco. So PSG can still race to win the title, and yes you're right PSG is still the favorite team so it's possible they can still secure the title. Mbappe yesterday became hero on French team with 2 goals, Mbappe performance in scoring is actually still great, although Mbappe performance with PSG this season is not that impressive but yes is temporary.
You're right though the league haven't gone far and the gap between them and the league leaders is not very wide making possible for them to be able to catch up easily, even though they've underperformed in their recent matches, PSG are still very strong league contenders and I won't be suprised if they win the league again this season, but I'm very sure that PSG won't win the Champions League, their performance in their group is not convincing and I don't think they'll be able to stand tougher teams.
Mbappè has a very big role to play this season before he probably leaves PSG, their team is balance but what they need is focus and more connection on the pitch to get better results and i believe the goals Mbappè scored against Netherlands would boost his moral when he returns to the team after the international break.