That one on Marvel musical continuity is pretty important, and it's not something I noticed until recently when I was trawling through reviews for film soundtracks. The cases where they lean on consistent character theming between films is really incredibly bare, and almost never happens between films where they change composers.
Age of Ultron was a massive outlier in that regard, with Tyler and Elfman lifting cues from Silvestri's work. Everything else has been very inconsistent - even in the original Avengers movie, the only standout recurring motif was the one for Captain America's arrival and only because Silvestri worked on The First Avenger before that