I think one major reason why the sequel trilogy (and especially TRoS) was so unsatisfying for me was because of the decision to let each of the three individual directors of each movie has full creative control of their respective movies without even bothering to make a full outline of the plot of the whole trilogy. Seriously? You're going to set out to tell an epic story encompassing three movies each costing hundreds of millions of dollars (to say nothing of the marketing costs), hundreds of thousands of man-hours by the cast and crew, and betting the reactions of a fanbase consisting or literally millions of people and trust the plot of this story to the method of chain-mail writing?
That is completely absurd.
The only stuff I've seen of J.J. Abrams is the 2009 Star Trek, TFA, and TRoS, all of which had severe storytelling flaws that could have and (in the case of TRoS) did ruin their stories for me. I haven't seen any of his other works, but what I did see decidedly did not impress me as to his storytelling skills. I left the theater disappointed in TFA, because I thought it was too much of a rehash of A New Hope. Though I do have to admit that after repeated viewings of TFA at home, it began to grow on me. TLJ had its issues, but I honestly thought it was a better story than TFA simply because it refused to be a rehash of The Empire Strikes Back. Say what you will about TLJ, but at least it seemed like a fresh story, especially with the theme that it's your actions, not your bloodline, that define who you are. But TRoS seemed like a fundamental F-U from Abrams to Johnson from the scene where we see First Order TIE fighters hyperspace-skipping after the Millenium Falcon (something that TLJ established could only be done by large Star Destroyer-sized ships because of the bulky computing power needed for the tracking machines), to retconning Rey being a "nobody" and instead making her Palpatine's granddaughter (and thus begging the question of whether Palpatine doinked some random woman to get her pregnant with his son before or after (*shudder*) he got his face melted by Mace Windu), and all the way to the climax of the movie where Rey managed to defeat Palpatine's Force Lightning, something that Windu couldn't manage without getting thrown through a hundred-story window, simply because she had an extra lightsaber.
So that's the culmination of the Star Wars Saga: "If you want to take on a Sith Lord and win, make sure you have a backup weapon"? That's something that virtually every gamer learns from their first RPG session! That's hardly the stuff of epics.
As for whether or not the sequel trilogy get "decanonized" or whatever, the whole thing strikes me as utterly irrelevant. The movies are out there now. They're made and can't be unmade. Even if "Overlord Doomcock" (gawds, only someone as pathetic and misogynistic as an incel could give himself such a nickname) or whoever manages to get Disney to somehow "decanonize" the ST, all it will effectively do is start a bunch of useless flame wars arguing about "head canon" and which Star Wars stories do and do not (or should and should not) qualify as "official canon." I've always found such arguments as useless and pointless. And even if the ST is decanonized, what then? It's not like Disney is going to set out to somehow retell the "real" ending of the Skywalker Saga. Carrie Fisher is dead so Princess Leia is not going to appear in any future Star Wars stories. I don't know about Harrison Ford reprising his role as Han Solo after TRoS had him appear as...what? A (non-Force) ghost? A hallucination? A guilt-induced delusion that could be seen only by Kylo Ren? From what I can see, it would just be too impractical for a number of reasons for any retelling and/or retcon of the Sequel Trilogy. There's no way to Verbal Backspace the Sequel Trilogy; it's out now and will always be there.
As for the Rian Johnson trilogy, if it ever does come out, at least it will have only one person at the helm and can at least have the benefit of a single author creating its plot, instead of the cluster f*ck of having multiple authors f*cking it up by not even outlining the story.