Both of those are interesting. I think it says something that Gaurdiens of the Galaxy has the most memorable soundtrack in the MCU at this point because over half of the soundtrack is '80s music and they're all relevant in-universe because that's the era one of the main characters is from.
I think the 2nd video comes down too hard on Hans Zimmer though. Plenty of his stuff has melody and themes and are obviously his (Dream is Collapsing, Mombasa, Up is Down, The Kraken) and not generic at all. The thing with electronic music is that really exposes how well the composer knows how music works and how well they can effect people with it. And Hans Zimmer knows how to write memorable music. He is however the pioneer of electronic movie music though, so it's easy to see why he gets copied so much, but that's not really his fault...
One thing that neither video touched on is how the MCU is an adaption of comic books and the effect that could have on a soundtrack. Starting with how comic books don't have soundtracks, but how they have tones of sound effects. TBH, the things I associate with comics sound-wise are things like how many different kinds of punches, bangs, thumps, laughs, shouts, etc. can be conveyed with text effects. Same thing goes for character voices by the way. Character voices are the same way; I don't hear voices so much as I "hear" the different kinds of speech bubbles and the fonts of the text inside those bubbles. I guess what I'm saying is that I'm okay with the MCU not having a memorable soundtrack because that's not what I'm there for; I'm there to see a live-action version of a comic book and those don't have soundtracks.
Another thing is that composers have been "stealing" musical ideas from each other since time immemorial. It's kinda funny to look back at what Baroque, Classical and Romantic composers thought of each other and it turns out that they weren't all that different from composers today. It's just that it took longer for musical ideas to spread. So you'll totally see composers slamming each other over stealing ideas, writing garbage music, etc. In other words, music in general has been dealing with this for a very, very long time.
Speaking of copying musical ideas... the very first original film soundtracks were written by people who studied under Romantic composers. So a lot of the very first soundtracks are nearly indistinguishable from Romantic music (the original King Kong soundtrack is a good example). Interestingly enough, most Romantic music was all about painting a picture in listener's head with sound. So a lot of composers just ported over Romantic music ideas into the movies and found it worked very well.