Barcelona were more at the middle, not too good performance but also not bad for a team with young players who are still in the beginning of building their carrier except for Lewandowski who already knows more about the game. Barcelona players needs a lot of game time to be able to understand the game better, this coming season might be something different to watch. Last season there was no competition for the La Liga, checking the points difference between Madrid and Barcelona is too wide, which makes Barcelona performance look poor.
Next season, Real Madrid will also have a more fierce and fierce squad, so this will also prevent Barcelona from challenging for the title in La Liga again. Even though the facts you say don't rule out the possibility that Barcelona will be much better than this season. Because apart from there being still many young players in Barcelona, the team will also be trained by a new coach who may have new methods that will be implemented in the Barcelona squad later.
Barcelona with its new coach will most likely not be able to match the level of Real Madrid which is already quite strong now, no new coach can make a team improve immediately without any process, especially now that Barcelona is in a very bad state.
Meanwhile, Real Madrid is now quite strong, especially next season they will have the best player in the world, namely Mbappe, so it is very likely that their strength will be much stronger so it will be difficult for Barcelona to catch up.