The Dortmund team is strong but they are not playing well against big teams. The performance of the players becomes very poor when the team performs against a bigger team. In the last match they lost badly against Bayern Munich and failed to score a single goal.
If Dortmund performed badly against a bigger team, that means they are not strong enough. Several years ago, I can agree that Dortmund is a strong team. They could beat Bayern Munich and they could strong teams in UCL. I still remember Dortmund has a strong squad in the season 2011/2012. At that time, they were the German champion and German cup winner. Now, their squad is no longer strong enough. It is proven that they were defeated by Bayern Munich with 4 goals in Bundesliga match.
-https://www.transfermarkt.com/borussia-dortmund/kader/verein/16/plus/0/galerie/0?saison_id=2011
-https://www.transfermarkt.com/borussia-dortmund/erfolge/verein/16
The Newcastle team is much stronger now. Day by day this team is getting more stable. They beat big teams like PSG in Champions League matches. They beat Manchester United 3-0 in the EFL Cup match and the team beat Arsenal in the last Premier League match.
It is true that Newcastle is getting stronger. They could beat bigger teams, they even ever lead the group F in UCL. But their position dropped to the 3rd place after they were defeated by Dortmund. I think their performance isn't stable enough but there is a good progress on the performance.
This is why the Newcastle team is considered the favourite in the next match against Dortmund.
Since Dortmund could beat Newcastle in their home in previous match, it is a bit difficult to predict which team to win the next match. I think both teams have the same chances, they actually almost have the same quality of players. It depends on how they could keep the good mentality during the match. Which team that play more confidently, probably has a bigger chance to win.