This season is the time for Mbappe and Dembele to work hard on PSG's front line and several other players must also be able to work hard on their respective lines so that PSG can compete better in the group stage in the Champions League and in Ligue 1 such as usually. Because it is too late for PSG to hope for a finishing striker like Haaland in their front line, so PSG can only hope that the existing players can work hard during this season.
Getting a striker like Haaland would be a miracle for PSG anyway. Things are not looking good at PSG at the moment. Especially after losing their important players, Mbappe will not be next year, so they will have to hold on tighter this year. This year may be better for PSG, of course, who will add to their squad during the interim transfer period, all will be shaped accordingly.
Honestly they do not need a striker like that because they have Muani already for that position. They need a left winger, and if they can get a great left winger, then they do not need Mbappe anymore. Think about it, they are using Muani as more like a striker right now and Mbappe as a left winger in some games, that's still going on.
I believe PSG is getting ready and they are going to be quite good when the time comes, they are already good but they are trying to build that team for the next 10 years and that's going to be amazing, as long as they keep their players and build something strong like that, they could be finally getting one UCL eventually in the future with this amazing new young squad on their roster.