I still can't really understand what's so incohesive about it. Episode VIII picked up on threads from VII and IX picked up on threads from VIII.
The Force Awakens
The resistance is searching for Luke who has gone into hiding after his failed Jedi academy was lost.
Rey & Finn form a friendship, as do Finn & Poe (maybe slightly oddly not Rey & Poe).
The First Order decimates the New Republic leaving only the small Resistance to fight them.
Kylo Ren is shown to be prone to fits of rage and solidifies his ties to the Dark Side by murdering his father and letting go of the past.
Rey goes to Luke in exile.
The Last Jedi
Luke is reluctant to train another student after his failure with Ben Solo (as established in the previous).
The Resistance is on the run and Poe is being brash with their limited resources.
Kylo Ren destroys his helmet in a fit of rage (as established in the previous).
The Finn & Rose mission does improtatn character work and isn't really incnsistent, but perhaps a little bit of a meander.
Kylo Ren connects to Rey (mysteriously) and tries to convince her to see his side - to let go of the past which has become an important philosophy for him (as established in the previous).
Kylo Ren kills Snoke and assumes control of the First Order but Rey resists his offer to rule by his side.
Rey is told that her parents were "nobody" as he was told by Snoke, but she doesn't necessarily believe that it is true (the tone is duplicitous). The theme is that we create our own destiny.
Luke realizes that he has been wrong and must step forward to help, which he does by buying time for the Resistance to escape by playing on Kylo Ren's (established) rage.
The Rise of Skywalker
Supreme Leader Ren is in charge of the First Order (as established in the previous)
It turns out Palpatine was behind everything (a bit out of left field but it works), including Snoke, and is who connected Rey and Kylo Ren (as established in the previous).
Kylo's repair of his helmet is symbolic of his reconnection to The Sith proper (this was always just about showing Adam Driver's face - don't hide the money maker, right?)
The quest to find Exegol leads Rey to another vision of a dark future for her if she follows this path (as shown previously).
Rey leanrs that her parents really were "nobody" as they were in hiding because her father descended from Palpatine - a clever twist (but not inconsistent, intentional or not)
Rey runs to exile, as is pretty much par for the course for the Jedi (as established in the OT).
Luke's spirit approaches Rey and says that he was wrong to be afraid to train her (as established in the previous). Luke had already learned this which is why he helped on Crait.
Kylo Ren faces what he did through a vision of his father and is finally rejects the Dark Side completely.
Palpatine manipulated everythign to draw Rey to him but she defeats him by embracing her true nature as a Jedi.
Now it's totally fair to criticise the story points, the narrative, the execution, but to me it seems like "inconsistent" is just an argument made as shorthand for "I don't like it" because "if I didn't like it how could it possible have been done well?" By the same measuring stick the OT was incohesive.
A New Hope
Luke is sweet on Leia and there is a love triangle.
Darth Vader is not Luke's father.
The Emperor is not mentioned.
The Empire Strikes Back
Luke kisses Leia and seems pretty proud of himself
Suddenly Darth Vader has a boss
Darth Vader is Luke's Father
Return of the Jedi
Luke has a sister and it is Leia
Lucas didn't have a full plan either, BUT - everything totally works of course, "form a certain point of view." That's why I just can't understand the harping on the Sequel Trilogy over this stuff. Anyway, back to your regularly scheduled Kathleen Kennedy bashing....