I have Wandavision down a notch from this. I think the concept, premise, ideas, and the acting are all top-tier, but the actual execution was a bit hit and miss. The premise of starting in a series of sitcoms was brilliant, but they didn't really do enough with it.
I agree, in that the last three episodes did not live up to the promise of the first six (and the "final fight" with Wanda and ... well no spoilers ... flying around pew pew pewing at each other was just such a terrible way to end the show) ... but I'm fine with it up there, because it was pretty daring in terms of launching the D+ shows, and they've carried through with that original promise.
IMO, there is a clear "best" show on D+ so far (Ms. Marvel), and then the next four best shows (Wandavision, Loki, Moon Knight, and She-Hulk) are all in some arguable order. Heck, I could see someone making an argument for Hawkeye in there as well ...but, you know ... Hawkeye.
Just. Not. The Falcon and the Winter Solider. That was perfectly cromulent, but no more.