Lewandowski is a difficult topic for Barcelona right now as on the one hand I think they wish he could perform outstandingly for maybe one or two seasons more until they really have a world class striker to substitute him. On the other hand the ties are getting loser between the player and the club as there have also been first arguments between Xavi and him and I think if Lewandowski doesn't score a lot of goals in the next few weeks, these cracks in their relationship will only get deeper and everything will get worse. I don't think they have a bright future together.
I personally think Lewandowski will be released this season to the Saudi Pro League the reason Lewandowski is no longer reliable and his contribution to the team has been low this season so it was the right choice to let him move, especially since the Saudi Pro club was willing to pay a high price to bring him in. Previously I checked the top scorer list and didn't see Lewandowski name so I assume he is no longer able to compete, Barcelona should realize that there is nothing more they can expect from this 35 year old man.
Lewandowski and Xavi has small conflict because recently Xavi has complaining to Lewandowski performance for each matches this because Xavi thought Lewandowski is too lazy which make he didn't gets much opportunities to scores and this also caused why Lewandowski goals records was decreases compared to last season and Lewandowski has a contract until 2026 but recently there was a rumour he will be sell to Saudi Arabian clubs because some of those teams were showing their interest to him
But apparently the drama was ended because Lewandowski has decided to stayed at Barcelona for at least until end of his contract and i know it's not good to rely on Lewandowski to scores goals because just like you said he is not young anymore and Lewandowski also cannot able to performing well again just like when he was showing at Bayern Munich but admitted or not for now at the Barcelona squad there was no striker who even much better than him so selling him it is very risky and Barcelona should be immediatelly look for new striker because front lines is one of their weaknesses this season and i know they already got Vitor Roque but this player is still young and lack of experience in Laliga