the first one is okay as a set up tbh, not much problem with it other than it being kind of a re-hash of a new hope
the big problem with the 2nd movie is just a lack of continuity with the first. they KNEW they were doing a trilogy, unlike the original star wars trilogy where had the first one been unsuccessful it could have been a standalone film
the characters change, in the first movie rey and black guy have some sorta romance going but that never comes up again in the later films, in the second movie, kylo kills snoke seemingly setting him up for some sort of redemption down the line, while this happens in a sense in the third movie it's still kind of out of nowhere, throughout the third movie he's still actively trying to thwart the protagonists' plans and generally speaking very angsty.
There's canonical implications and shit like that I could get into but just generally speaking the trilogy as a whole suffered from a complete lack of planning. Say what you want about the MCU but you can tell that despite the huge cast of actors, directors and writers that have come and gone over the past 15 years or so they deliver a consistent product and one typically leads right into the next in a way that's not intimidating to get into but still feels like a shared universe.
Somehow, Disney, with what I can only guess was one of the biggest acquisitions in media history completely fucked up their first foray, pissing off old fans, confusing new fans, and missed out entirely on creating a new generation of star wars fans who will buy star wars bullshit for the next 20-50 years.