Regarding PSG's dominance in League 1, I don't think Luis Enrique needs to worry too much even though Mbappe will leave for another team in a more different league. But Luis Enrique must also have time to think about who he will target in the next transfer window by preparing sufficient money. Because if the target is a player whose level is not much different from Mbappe, of course the costs that must be prepared are not small and I am sure that PSG has the ability to do that.
Supported with good financial is not problem for PSG looking for replacement for Kylian Mbappe position and keep easily for dominating in Ligue 1, Luis Henrique will find other players with level gap not much difference from Mbappe but how possibility for PSG will dominance in Champion League without him? Currently, PSG still hasn't official announcement who will replace Mbappe position after announcing will leave PSG next season, some of target from Victor Osimhen, Rashford not confirming yet because PSG still waiting with the bid offer price from Napoli and Manchester United.
PSG seems focus for this season for winning Ligue 1 and working best result in Champion League, they will face Barcelona on quarter final and few week before this season ended seems they will announce with players replacing Mbappe position.
With Mbappe or not PSG will always be dominate Ligue 1 this because this team supported by strong financial conditions so they can able to bought the players they want probably as the replacement of Mbappe and i am sure after Mbappe leave PSG this summer then there is transfer saga for this team because most likely PSG will bought the players with expensive price and indeed so far there was some players who linked to them just like the names which you mentioned above but so far this only media speculation moreover the transfer window hasn't opened yet
Regarding PSG chances in Champion league although since joining with PSG Mbappe always be playing on that competition but PSG was never able to gets the trophy even when Messi and Neymar still at this team PSG always be failed in Champion league and this season is the last season for Mbappe and it could be very fantastic if Mbappe can bringing PSG to gets the trophy for the first time and their first test is Barcelona however i have been realized in Ligue 1 this weekend PSG will facing Marseille and very interesting to know whether PSG can able to beat Marseille or not but they have to beware of Marseille because under new manager Marseille has showing significant progress