Lewandowski plays one of the special roles in the Barcelona team. He joined the Barcelona team and helped the team achieve great things in an impossible way. Next season this player will help the Barcelona team tremendously to do something great in the Champions League.
In the last two seasons, Barcelona has always failed in the Champions League including last season and I also don't see more great things done by Lewandowski even though Barcelona managed to get the La Liga trophy this season because their eternal rival is not so consistent in La Liga this past season, so the things that Lewandowski did to Barcelona in this past season were normal and natural, not an impossible thing for him. And next season it looks like it will be much more difficult for Lewandowski to get much better achievements than this season.
Barcelona's team is playing very well this season. But after Messi left the team and Koeman coached the team, Barcelona's performance was completely unstable. Barcelona was a team that was almost overwhelmed. Barcelona also had to face a lot of problems to win against weaker teams. After Xavi became the coach of the team, the overall position of Barcelona started to improve. And this season Barcelona was aiming for the La Liga title. And they managed to win it. Next season maybe Barcelona will play better in La Liga as well as the Champions League.
The transition of moving players or coaches is very natural for a club and what Barcelona is experiencing is one of the processes to be better in the future. Had fallen many times, but since Xavi's era as Barcelona coach began, we can see the turning point for this Catalan club by winning La Liga this season and they deserved it. About the champions league I think there will still be some stages they go through and the importance of consistency for a team is to be able to achieve that target and that's what a team really needs.
so far, we can see Barcelona competing and even winning La Liga again next year, but the talk about the Champions League is still far in my opinion, they have a long way to go to be able to compete with teams like Bayern Munich, PSG, Man City..etc Lewandovski is not the best they can get as a forward, he doesn't seem to fit that well with their style, he is kinda on and off in their matches, they need more to win something big like the Champions League.