We had the same problem with versions 4.5.6 and 4.6.0 on some projects, and we finally realised that it was a problem with imports in our custom plugins. Try to check if you plugins can be built properly.
Changes in imports, e.g:
// before
import { Button } from "@strapi/design-system/Button";
// after
import { Button } from "@strapi/design-system";