When I open WebStorm I got "The application “WebStorm” can’t be opened." and "255" Permanently deleted user Created April 19, 2021 17:04 OS: MacOS Big Sur 11.2.3 That's what I see
This error can occur for dozens of reasons (see http://www.cleanmacoserror.com/fix-mac-error-code-255/) - MacOS error messages are not too verbose. Did you try uninstalling the IDE and re-downloading it from scratch?