Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpunit/phpunit ^9, found phpunit/phpunit[9.0.0, ..., 9.6.22] but these were not loaded, likely because it conflicts with another require. Problem 2 - drupal/core-dev is locked to version 11.0.10 and an update of this package was not requested. - drupal/core-dev 11.0.10 requires phpunit/phpunit ^10.5.19 -> found phpunit/phpunit[10.5.19, ..., 10.5.44] but it conflicts with your root composer.json require (^9).