I agree that the TV side of things was the biggest problem, and Marvel leadership has publicly admitted as much. With that said... I wouldn't say their track record in the post-Endgame phases were decent to excellent, at least in my opinion.
No one asked, but:
- Spider-Man: Far From Home - fine, very forgettable
- Black Widow - never justifies its existence, flat despite a game ensemble cast and some good additions to the character roster
- Shang-Chi - one of the better ones, for sure. I really like Shang-Chi himself, but the film loses steam and never recovers once they travel into the hidden realm
- Eternals - everyone was out for blood on this one for a variety of reasons, but it's probably the best-looking of these films and is more narratively ambitious (and thus interesting) than just about everything else here. That counts for a lot, even if it doesn't all work
- Spider-Man: No Way Home - I had a fun time in the theater, it's an enjoyable ride, and it was great to spend time with some of these villains again (even Electro, who naturally deserved more the first go-around), but it's still a ride more than a film; I've forgotten most of it and have very little desire to revisit it
- Doctor Strange in the Multiverse of Madness - falls into that decent category. Gnarly imagery, but the story's elements never really clicked together for me, and it felt like they left a lot on the table
- Thor: Love and Thunder - I'll controversially say I'm not as hot on Ragnarok as everyone else (it has great parts, but it's two different movies awkwardly slammed together). I even like Waititi's early films a lot, but he's unmoored here; Christian Bale is doing compelling work here, but the rest is a sloppy slog
- Black Panther: Wakanda Forever - extraordinary circumstances robbed us of what probably could've been an excellent follow-up. Coogler does his absolute best with what he was able to cobble together, and there are a handful of moments that shine, but at the end of the day, it's lost without Boseman. It doesn't help that it came out right before Avatar: Way of Water; Panther's Atlantis isn't even in the same league, visually
- Ant-Man: Quantumania - I don't think I have to justify this one, everyone agrees it's a mess
- Guardians of the Galaxy: Volume 3 - very good! Does the extremely hard job of bringing this trilogy to a close and tackling the seemingly impossible alt-Gamora problem. One side effect of it being so damn depressing at times is I don't have a lot of desire to revisit, despite its empirical quality
- The Marvels - another decent one, but only barely thanks to the likability and chemistry of the cast. The first Captain Marvel was breathtakingly terrible, so this one is better by default, but it still lacks an actual compelling story.
- Deadpool & Wolverine - not sure if we're counting this one? Basically the same notes as Spider-Man: No Way Home.
- Captain America: Brave New World - wheels are really falling off here. Embarrassing that they put this out, and that it cost what it did. Fallen a long, long way form Winter Soldier
- Thunderbolts - To your credit, another decent one, but it's also got that feeling of "been there, done that," and there's some really offputting rubberbanding of characters morality/track records that the film never really reckons with in a satisfying way
- Fantastic Four: First Steps - a very rock solid cast and aesthetic in search of a better story
So by my count you've got two that I wouldn't put at "excellent," but at least "quite good" and at or above the average level of the pre-Endgame output. Three "decents" between Doctor Strange, Marvels, and Thunderbolts. I just can't put the Spider-Man films at that level, which I realize probably isn't a popular position.
I think a cinematic universe only sustains itself if it has more hits than misses over time. That hit/miss ratio has deteriorated,
especially if you count the television releases (and I think you basically have to).
Doomsday and its follow-up is basically going to be a decision point for me: Can they convince me that these films are still worth my time, or is this an off-ramp? The trailer sadly doesn't give me a lot of hope, but that doesn't mean the final film won't work.