The process for Szczęsny to join Barcelona is getting more interesting for me. Szczęsny is lucky because of Ter Stegen got injured in Barcelona and he can have the chance to play in this team otherwise Ter Stegen would have played in Barcelona for years considering the performance he had in this team.
Also, it seems there is a Polish plan in Barcelona for hiring Szczęsny. Jerzy Dudek the former Polish goalkeeper of Real Madrid said Szczęsny is a better goalkeeper than Ter Stegen. also Robert Lewandowski had an effective role in hiring Szczęsny.

It's just a coincidence, nothing more, because Szczesny decided to end his career, and this offer was most likely unexpected for him, but it's hard to refuse. Whether he is better than Ter Stegen or not is a very debatable question, but in this situation the choice is small, so Flick took the path of least resistance, there is a whole season ahead and it was impossible to be left without a goalkeeper. And Lewandowski will help him get used to the team faster.
Szczesny certainly will not refuse this offer because he also wants Barcelona, maybe the deal has been done, we just have to wait. Barcelona in this case did move quickly after losing their main goalkeeper and Stegen was confirmed to have a serious knee injury. Barcelona even confirmed that Stegen would undergo surgery and is expected to recover until the end of the season. Of course this time Flick wants to bring in Szczesny, it's natural because Stegen's injury is a big loss for Barcelona, especially Ter Stegen is their team captain and main goalkeeper.
Indeed, there is Inaki who is a young and talented goalkeeper, but considering Barcelona's very tight schedule because of the many matches that must be played, of course Barcelona needs a goalkeeper who has high flying hours and more experience.
What's more interesting and maybe this is just a coincidence. Szczesny once said in an interview, that there is only one thing for him in the coming year, namely watching El Clasico (meaning as a fan), because he always wants to see it live. Without him realizing it, now it might become a reality, not even as a fan but as a player.