Three matches can certainly be a stumbling block for Stuttgartf this season in maintaining their position in the Champions League zone, but I think they will be able to get at least 7 points in those 3 games, I don't see if Munich and Dortmund will be able to prevent Stuttgart from being able to get 6 points in these two games, currently the performance of Munich and Dortmund is no longer as great as last season and besides that the busy schedule between the Champions League and The Bundesliga certainly has to force them to choose one as the main focus this season, the game against Dortmund has a short span between the Bundesliga and the Champions League so I think Dortmund will not risk fielding many main players in the game against Stuttgart later.
The only difficult match for Stuttagart may only be Leverkusen, so far Leverkusen still has performance and consistency in winning every game, but there is nothing wrong for Stuttgart to play optimally in that match at least to be able to get 1 point like they did in the first Bundesliga match of the season against Leverkusen.
Bayern Munich's motivation in the Bundesliga will no longer be too great because they almost certainly have no possibility of defending their title, and that will be an advantage for Stuttgart and for the match against Dortmund I think it is quite balanced because in terms of strength Stuttgart and Dortumnd this season are not very different and even in terms of consistency, Stuttgart is a little better.
With the current superiority in points and also the consistency that Stuttgart has, I think it is very likely that they can maintain their position.
Yes, Leverkusen might be a difficult opponent for Stuttgart, but losing 1 match will not have a big impact on their position.