Only available for 2022, even in their repository of documents which has sustainability reports for multiple years. https://www.samsung.com/global/sustainability/digital-library/policy-document/

We cannot directly find the previous document on their website but it's searchable: https://images.samsung.com/is/content/samsung/assets/uk/home/SEUK_Modern_Slavery_Statement_2021.pdf

Samsung does not provide links to modern slavery statements from previous years either on the website or in current statement.