According to what I've been reading, after Nuri Sahin's dismissal for not meeting expectations, Dortmund had Erik ten Hag as a favorite, who comes from a complicated tenure with the English team Manchester United. However, there was a change of interest, and they turned their sights to Niko Kovac to lead Borussia Dortmund, as it's a new beginning and aligns with the ambitions of this candidate. Therefore, there are good omens from the fans because he could bring the necessary change to recover the club's prestige. The financial demands of Kovac are not clear, but it seems to be within Dortmund's budget.
Compared to Erik Ten Hag, I think for some reason I prefer Niko Kovac because I think he has quite good experience in the Bundesliga and maybe he is suitable to coach a big club like Dortmund, previously he was the coach of Bayern Munich and won the Bundesliga title and the DFB Cup in the 2018-19 season and also became the coach of Eintracht Frankfurt winning the DFB Cup title and the Runner-up position in the Bundesliga so if he coaches Dortmund, it is possible that he can improve the performance of this club which is currently slumping.
I think Niko Kovac has a better understanding of the league as a manager because he has served as a manager for different Bundesliga clubs so definitely he has an advantage over ETH in the race for the managerial role of Dortmund besides after ETH’s Manchester United failure it will raise questions on his ability to change things in a struggling side like Dortmund which is desperate need of a change. It is possible that Kovac can bring improvement because he has better experience in the league.