I'm surprised by this news, but given the revolving door of Lucasfilm writers and directors, I suppose I shouldn't be.
The writers cite schedule conflicts, but I have to wonder if this has something to do with the huge backlash over the GoT final season (and last episode). I haven't seen GoT myself, so I don't have an opinion either way, but I read a lot of fallout from that. I can't say I blame the writers; focusing on their own projects will probably be less likely to incite audience anger and frustration than working on another major franchise.
The first movie in the new series was slated for December of 2022, which means that Lucasfilm will have to hire new talent fast, or that date will have to be cancelled while the company gets its bearing again.
Meanwhile, work on Rian Johnson's proposed trilogy hasn't come to a complete stop, but Johnson has been busy with another film (Knives Out), and negative fan backlash to The Last Jedi suggests that all parties involved might take it slow for fear of more audience fallout.
So, for the first time in several years, there isn't a Star Wars film in production or with a release date (beyond Rise of Skywalker in December). That's fine; I don't mind if the franchise gets a bit of rest, although in this case, a "rest" still means new TV shows on Disney+, as well as new video games, comic books, novels, etc.