Yeah, you could say that.
My thing with Mark Millar is that I think he’s a better concept/pitchman (What if superheroes were real? What if Superman had landed in Russia?) than he is at executing his own ideas (there’s a reason why a lot of his comics get turned into movies, and that those movies tend to do well but tend to involve the director making some significant changes to the plot, characters, tone, etc.).
When Millar executes his own ideas, not only do they often end up lacking in depth, but you also get some really icky stuff creeping in: leaving aside Wanted’s misanthropic hatred of its own audience, the treatment of black women especially is really grotesque; the graphic novel of Kick-Ass likewise has some weird stuff around both gender and sexuality and race. Throughout a lot of it runs the worst part of 90s comics – the idea that violence, sex, sexual violence, and characters acting like assholes makes something edgy, mature, and art.
His runs on the Ultimates (my beef with him started with his decision to make Captain America a jingoistic conservative, but I wasn’t a huge fan of having Bruce Banner’s rage powered by his sexual failures wrt to Betsy Ross, or re-enacting Ant-Man’s domestic violence, etc. etc.), Ultimate X-Men, etc. have a somewhat more sanitized version of the same thing.
So yes, the MCU borrowed from some of his setups and visual motifs, it’s highly noticeable that they jettisoned his characterization and themes in favor of their winning strategy of making their hero characters likeable, good people who (mostly) get along with one another, and who we enjoy watching being together. This is why this moment was so important:

Now, I have heard that Millar has matured somewhat recently and his recent works are a lot better on this front – less misanthropy, less crude deconstructionism for its own sake – so I don’t want to write him off entirely. But he was a big part of what burned me out on superhero comics in the early 00s, so I’m just going to let it pass me by.