Ok I tested, and if I set English as language, it works, and the error disappear, thanks for helping!
I tried to deactivate all the plugins one-by-one and have them all deactivated at once, but the error still appears; I noticed that the first “Notice” paragraph is related to something else, but the Fatal Error is still there when I try to go into Settings; Even if I changed the Theme (I used Twenty Twenty-One), the problem didn’t solve
WordPress version: 6.7.2 || PHP version: 7.4.33 || Language: Italian
