It seems all alarm bells go off the minute you attempt to manage multiple locales.
See for example Strapi's localization, which has been broken for years with no fix in sight (due to how its designed) [See: https://github.com/strapi/strapi/issues/12538]
I feel like one of the core values of any CMS should be excellent UX but that seems far from the truth for headless CMSs.
I've also tried others like Directus but Strapi seemed the most mature of the bunch