I may not call Phase 4 in that way, but I understand and agree with you in some ways.
Everybody said Star Wars cinema was doing fine because it made incredible numbers in box office and didn't take production conflicts between studio and filmmakers or divisive views in audience as big deal. But once Solo came out and failed in box office, Disney halted all spin-off movies and didn't know which story direction the last chapter of Skywalker saga should go. They still could't tell how to handle SW in film territory at this point.
For MCU, something similar but less serious are happening. Eternals didn't work well for whatever reasons, but it was ok for the franchise and hurt nothing. Nobody could hit the mark every time. Spider-Man: No Way Home, a movie with fun and messes at the same time, was something they couldn't finish until the very last minute. Some may argue that Hollywood blockbusters are always busy with their middle and post-production. And I don't disagree with that. But after Marvel change the director and push their whole slate back due to the major reshoots on Doctor Strange 2, I don't think they're still in a very normal state.
I don't think those numbers are disappointed or average for Marvel and DS2. But it's fair to say Phase 4 in movie aspect is not that stable right now. The vitality of the franchise allow them to take the hit once or twice even more but never countless times. For SW movies, Solo is the point of transition those conflicts totally outbroke. For Marvel, it's not impossible that it would fall into the same trickier situation. Maybe just one more wrong step.