I have this issue with cursive/IJ upgrades occasionally. Suddenly the IDE will not recognize Clojure at all. I mean, it knows it's looking at Clojure app and I can start a repl, and the context menu options include converting to cljc/cljs and all that, but the code is all "new phone, who dis?"
Like, it should know what ns, defn and println are. Usually I get some kind of REPL error to send (which happened with this latest) and there's an update within hours or a day or two at latest.
I only mention it this time is that it's been going on for a while, and I've got version 1.10.1-2021.1, released on March 1st?