I strongly the best decision by barcelona is to sell him, though pedri was one of very important players in barcelona. You said Neymar has suffered the same thing as Pedri. But, there is a worse case in Barcelona: Ansu Fati's. Ansu fati's career being ruined by his injury.
Pedri's injury proneness will hurt his stability next season. I don't see a reason for Barcelona to keep him much longer, and this is not my first time to see barcelona's player gets ruined by his injury prone.
It would be the best option for Barcelona to sell every player who is prone to injury as in the case you said. Because Barcelona is building a more solid team with players they can rely on, it would be wise for players who are prone to injury to be released before it's too late because Barcelona can also use the money from the sale of Pedri to buy other players at this time. Apart from that, several cases that are almost the same and have happened to Barcelona in the past can at least be used as important lessons for him so that Barcelona can remain on a strong path.
This may be less effective although it can still be done.
Not without reason, Pedri and De Jong or maybe Kounde although vulnerable to injury but their performance has always been an addition to Barcelona's breakthrough power in terms of attack especially for the midfield where Pedri has always been a differentiator on several occasions this season even though he is vulnerable to injury.
In addition, if they let Pedri go then this will also be difficult for Barcelona's midfield especially for next season even though Gavi is certainly recovered but his adaptation will definitely take a little longer considering the long break after the ACL that requires more time to reach their best performance again and in a way this will also definitely interfere with Gavi.
But I do agree with the thought that eventually some unused players should be let go so that their slots are not disturbed and finances become more stable.
At the moment there are actually some players who have not stood out this season like Romeu or Sergi Roberto. If it's more extreme maybe they could sell Ferran who is in demand by Newcastle and look for other alternatives as replacements.