Are you using english or some other language on your site? If not english, updating to 5.5.1 might fix things for you, and have all the content turn up in admin again, as it contains a fix for translation bugs.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users
2022 was a big year for Advanced Custom Fields, with more capabilities, a new generation of ACF Blocks, a refreshed UI, and a new home. Our year in review post looks at advancements we’ve made and offers a glimpse of the future. https://t.co/HahJUCcyH4