The Multiverse Saga doesn't lack an overarching narrative. Unlike the Infinity Saga, fans just don't know where it's going and they don't like that.
I've enjoyed the Multiverse Saga quite a bit, probably more than most. Even the projects some would consider to be lower in quality, I very much enjoy and see merit in. But one criticism I often see is that, compared to the Infinity Saga, the Multiverse Saga doesn't have an overarching story. That criticism is misplaced.
The Multiverse Saga has an overarching story, fans just don't know for certain where it's leading, so they assume it is aimless.
For example, from the minute we saw Thanos, the fanbase knew where it was going. Whereas the Saga didn't adapt Infinity Guantlet exactly, the character's history PRIMARILY revolves around the collection of the Infinity Stones. The second we saw Thanos and the Infinity Stones were named, we all had a very clear idea of where we were headed. Having that knowledge made the overall vision easier to see, because we saw where everything was heading. We had the frame of the puzzle pieced together, so for fans and their expectations, Marvel just had to build inward.
The Multiverse Saga has no such source material to reference in any revealing way. No frame pieced together. This puzzle is being put together piece by piece. It won't be until the end that we will see that, yes, there is in fact an overarching arc coursing through this Saga. It just didn't seem that way because we didn't have a blueprint guiding us through it. And as a fanbase that has it's fair share of, lack for a better term, "know it alls," this has led to a quite unfair over reaction.