Although Lewandowski is 33 years old, he is expected to be able to continue his impressive performances for at least 2 more seasons. He has played very well in the last few years with Bayern Munich. And now he has taken on a new challenge in La Liga. Having played in the Bundesliga for a long time, it may take some time to adapt to the La Liga gameplay. Lewandowski is talented and experienced, he will be able to adapt to the players of the Barcelona team very quickly.
I'm sure he won't have any problems in terms of adaptation, he can handle it easily considering his past experience with Guardiola. Xavi's playing style is not much different from Pep Guardiola's, so it may be easy for Lewandowski to adapt to Barcelona's game this season.
I hope he does well at Barcelona even though I'm not their supporter so far. Lewandowski is a good player to hope to be a useful asset to any team including Barcelona, but I never imagined he would be at Barcelona after being a Bayern Munich player for so long.