You're right they started very poorly but currently they've picked up and are doing well, currently they're in the 4th place on the table and are having same points with Bayern Munchen who're in the 3rd place, with just 2 points separating them from the league leaders Leverkusen, just like last season Dortmund are very strong contenders, though they're not very strong like they were last season due to the lose of their star player Jude Bellingham, if he were still in the club I believe they would had been in a better position and probably win all their matches so far.
They're still one of the team that's kept an unbeaten record so far and if not for the 2 draws they had they would had probably been at the top of the league, Dortmund are doing fine and are on the right track in their domestic league but have a very poor performance in the UCl and I doubt if they'll move to the next round.
when talking about Dortmund, it cannot be denied that the start of this season has been very bad, but I dont want to be too quick to make decisions about some of the top teams in the Bundesliga considering that there is still a very long way to go and I will speculate after entering February 2024 that it will be certain which team will be has a safe position in first place in the standings.
on the one hand, there are still many changes that will occur after the transfer window opens again and we will definitely see very clear changes to a team that looks bad like Dortmund, of course they will bring in more players to strengthen their performance.