I enjoy the first trilogy and there are elements of Dark Phoenix that were good - the choreography and set pieces were great. But the characterisation was terrible. Because the writers had no plan for the rebooted series of movies, it meanders and contradicts itself, almost like every movie is set in a separate alternate reality.
There was no foreshadowing or effort to explain that the rise of Apocalypse must be as a result of the changes to the timeline from DoFP, otherwise the encounter would have taken place before X1, and no way could those amateurs have beaten Apocalypse. They squandered Angel's only decent storyline for shallow special effects, not that it was the same guy, who should have been aged about 8 at the time the movie was set. They took names of characters and applied them to characters who bore only a superficial resemblance to their comic counterparts and tried to mimic Civil War by having X-men vs X-men. Apocalypse was a poorly implemented super villain.
In order to do justice to the Dark Phoenix story an entire B-plot needs to be given over to Jean's descent into madness before moving into Dark Phoenix. We've seen that as Marvel Girl is is largely crap and then as Phoenix she rocks. THEN in the next movie they need to make her go cray cray. The only point of the story is to tug at our heart strings and we have to care about the characters to do that. X3 almost got there.
Far better for me would have been if Phoenix awoke Apocalypse in X3 and X4 focused on the Marauders setting out to help recruit the Horsemen of Apocalypse to capitalise on Angel's appearance. Then X5 and X6 could have been about trying to defeat Apocalypse, culminating in the Cable providing the revelation that both Scott and Jean are alive and in the hands of Sinister. Apocalypse isn't Thanos but they could had had some fun with him as a proper big bad.