This is an interesting move by Borussia Dortmund, they lost his brother years back to Real Madrid and now they've going after and signed his younger version, well Jobe was fantastic at Sunderland and such improvement at a younger age is what attracted Borussia Dortmund to him, if he could replicate what his brother did years back at Dortmund then it's a boost for the club next season, although I don't think he'll last long cause they might still loose him to another club it he shines, Dortmund are not that club that retains their younger talents, they're known for offloading them for heavy cash to bigger clubs and there's a possibility that Jobe Bellingham could me sold in a similar way like his brother Jude.
But one thing I've always liked about Dortmund is that they more often find young potential that they can develop in their team. We know that Haaland also shone quite brightly when he was at Dortmund which made Man City want Haaland at that time. Dortmund is a team that is able to find potential young players who they will develop into star players in Europe. Jude Bellingham is also the same as Haaland. And now Jobe Bellingham also looks like he could be the next player who is expected to be the same as Jude Bellingham and Haaland.
If Dortmund prefers to keep the young star players they have then this team should be able to compete more strongly in Europe or in the UCL. Unfortunately, this team is always unable to retain the players who have played well in the team.