Based on Samsung's update history, "R2" likely refers to — specifically its second major beta or stable rollout (sometimes codenamed internally with "R" for Android 12, and "R2" for a refinement). In 2021, the Samsung Community forums were actively discussing new features and issues.
In 2021, the r2 Samsung Members community became a vital hub for users to navigate firmware updates for One UI 4, decode build versions, and engage with a new gamification system. The community also featured a significant UI update in November 2021, which enhanced app stability and improved the user experience. For more details, visit r2.community.samsung.com . New Updates UI - Samsung Members Community r2 samsung community 2021