Sitepackage Builder should use `bootstrap5-rte.min.css` imo. it's already upstream https://github.com/benjaminkott/packagebuilder/blob/e580479eff38f1d2c0a4cf7842e2f0c95a68f820/src/Resources/skeletons/BaseExtension/bootstrap_package/Configuration/RTE/Default.yaml.twig#L9
