Robert Lewandowski is 34 years now. IMO, he has at least 3-4 years of quality football left in him. So it is too early to talk about his retirement. Ronaldo is performing exceptionally at the age of 37. The same can be said about some of the other players such as Goran Pandeev and Luka Modrić. Nowadays, players are able to maintain optimal form well in to late 30s. Lewandowski has scored 13 goals from 14 La Liga matches for Barcelona so far in 2022. That shows the sort of form he is in. And during the previous year, he scored 35 goals from 34 appearances in Bundesliga. 2020 was even better, with 41 goals from 29 matches.
Lewandowski still has time, at least 4 seasons may well play, but whether he wants to end his career in Barcelona? If he had stayed in Bavaria, he could have been in the Champions League now, but now with Barcelona he is in the EL and this is not what he expected. Maybe it's really more important for him to get a big salary, or because of the conflicts, he just didn't want to stay in Bavaria anymore, in the end everyone wants to find a place where he will be comfortable.