I think everyone involved is being very honest:
Marvel finally realized how badly stomped their Golden Goose now was. We all know the laundry list of issues that led to that point (Covid and the strikes breaking attendance habits, quick streaming service launches meaning there was little point to hitting the theater, a natural exit point in Endgame, Marvel splitting their focus between theatrical and streaming releases, Marvel wanting to reset by bringing in a new generation of characters and not supporting them well with good scripts / casting / directors / etc., Feige's successors not having the same luck* as him, Johnathan Majors' personal life, Multiverses meaning stakes don't matter, the film division copying the disastrous comic era of "Replace all the straight white guys with 'characters' with no personalities of their own other than representation points", etc. etc. etc.)
So Marvel's swinging for the fences, bringing back all the people from the golden age. But those creatives can see how desperate the situation is as well, and had Marvel over a barrel salary-wise; now a movie that had to be a blockbuster to keep the franchise relevant now has to be one of the biggest movies ever to not be a financial disaster on its own. (Not that I am sure that Disney cares if this is net profitable _if_ it brings audiences back to Marvel movies.) But expecting any movie to revive an entire franchise is tough; bringing in a ton of characters and keeping the plot clean is very tough; killing who knows how many of them and not losing their fans is even tougher; doing all of the above while also trying not to ruin 'keystone' moments (apparently Steve Rogers is never in the Cap suit because Falcon has that title, RDJ is 'Doom' because they want Iron Man to be closed. etc.) is a tough fucking ask for anyone - much less the people that last brought us the glory that is The Electric State.
I don't sense that anyone is half-assing it - even last week RDJ was hitting Cinemacon, an industry event that doesn't get stars, just filmed greetings - it's just that the task is so big and so likely to fail** that everyone knows this will likely be a disaster, and none of them will be in a Marvel (or possibly Disney) production in 2028+. Disney gutting the Marvel staff suggests they know what the reality is, after all.
*Not to repeat myself, but just as a reminder: At one point Feige was going to do a Star Wars movie to 'save' that franchise. What an absolute fall from grace.
**Dune 3 keeping the same date as Doomsday isn't the shocker - with the holidays and the January lull, people will have time to see two movies in theaters- but Dune (you know, the movie getting made by a studio that's about to be acquired and has no long term presence on its own) getting all the IMAX screens heavily suggests everyone else in Hollywood already knows how this is turning out as well.