Samsung has recently announced the One UI 3 Beta Program. It is now open for developers in the United States and South Korea. This new One UI is to bring Android 11 to the latest Galaxy devices namely the Galaxy S20, Galaxy S20+, and the Galaxy S20 Ultra. One UI 3 Beta will also be opened for other Galaxy devices but for now, the Galaxy S20 series smartphones will receive the major update first.
Link: One UI 3.0 Beta brings Android 11 to Galaxy S20, changelog here