I was going to chime in with something similar to this, but you beat me to it. So yeah, I pretty much agree. Before anyone points out that Spider-Man is the most popular superhero of all time and his films are always a license to print money... That's only true of the good ones. Make a bad film and the word of mouth travels and the film tends to break even at best (Raimi's third and Amazing 2 both did okay at best). No Way Home was a nostalgia nuke for the moviegoing audience of the last 20 years and it brought people to the theatre in droves. I know people who haven't been to a theatre since the pandemic other than to watch that one movie, and some of them went to it twice. You can't call the releases 'only flops' if one of the 10 highest-grossing films of all time is on your list. Then right after it Doctor Strange 3 came out and a lot of people were talking about how Marvel was back. Two good movies in a row, both bringing in good audiences. The buzz at the time was that the bad years were over and the MCU was back on top. Black Widow, Shang-chi and Eternals were just a brief aberration and we had some really promising stuff on the horizon: Thor 4 couldn't possibly be bad with Taika Waititi at the helm, and the highly anticipated Black Panther sequel would be right after that!
Then Thor 4 came out, and movie audiences showed up... To hate it. It made lots of money, but the buzz this time was not good. Questions were raised. How could Thor 4... Be bad? When Thor 3 was so good? Black Panther a few months later was... Fine. But audiences were immensely disappointed nonetheless. It was supposed to be lightning in a bottle, and instead it's just fine? Oh dear. Then Ant-man 3 was a disaster, almost everyone who went to it hated it. Marvel isn't back.
And that's where we are now. Audiences are Skeptical. The MCU isn't dead, but it's obvious something isn't working.
I mean, No Way Home was definitely an MCU movie. It directly incorporates the Snap and its effects into the story. Doctor Strange is a major supporting character. Stark Tech plays a big role in the plot. And when it was happening, nobody was calling it 'not an MCU movie'. They were saying things like 'Return to form for the MCU' and 'Marvel's back!'. It was the point that movie audiences started to care about the MCU again after the humdrum of the pandemic years. Doctor Strange 3, Black Panther 2 and Thor 4 all made plenty of money, even accounting for profit sharing and marketing budgets. Not smash successes, because it's hard to make huge bank on a $300 million budget, but they all made plenty of money. Guardians 3 can't be called a flop, it's at least broken by the most pessimistic measures. The rest? Yeah, they're disappointing. And, possibly aside from The Marvels (professional reviews bad, viewer reviews not so bad), also all bad films.
As for the mixed reviews statement... Eh, not really? Guardians 3 had pretty high ratings all around, and spectacular audience reviews (including from me! It was great!). Doctor Strange 2 was a bit hit-and-miss for critics, but for the most part people who watched it liked it and lots of people watched it. The buzz around the theatres at that time was quite positive.
I'm no Disney fanboy. But it's not like Marvel has been universally bad recently. They definitely need to change up something in the way they're doing things though. It's starting to look pretty clear that the cinema industry can't sustain $300 million mega-blockbusters at a rate of multiple films per year, and the audience clearly doesn't tolerate mediocre entries the way it used to in 2018.