Ramos definitely looked like a great player, I think it wouldn't be really that bad to just not even buy any new players and just play the same PSG team without Mbappe, they would still win the league with this squad if you ask me. But, they won't do that because they have money, and when you have money that means we are not going to end up seeing someone who will do further, we are not talking about anything more.
We should consider the fact that we are going to make it work one way or another, and that means that we are going to see something change. We should probably consider how that type of situation could change peoples perspective, because if they have money and not spend, that would not be ideal situation for PSG, and fans would be mad.
PSG without Mbappe will not be as strong as they used to be, and winning the League 1 title is possible but might be a bit tricky and difficult because we have seen teams that tried to compete hard against PSG, and if these teams keep the pressure next season and PSG decided not to sign more players before the beginning of the season, then Brest, Lille, and some teams might win the League ahead of PSG.
I am very sure that PSG will use their money to sign more players to get a good replacement for Mbappe and some world class players that will keep the team going so that they will maintain their reputation of been the best team in the league.