No official "Next Gen OS v37" exists from Samsung. The last official firmware for J200G is Android 5.1.1 (Lollipop).
What you're referring to is likely a custom ROM (unofficial) from community developers (e.g., on XDA or Telegram), possibly based on LineageOS / AOSP.
Next Gen OS v37 is reportedly based on the Android Open Source Project (AOSP). next gen os v37 for j200g
Versioning (v37): The version number could indicate a significant update from previous versions, possibly suggesting major feature additions, security patches, or a complete overhaul of the user interface. Quick Answer No official "Next Gen OS v37"
One UI Experience: Ports the look and feel of Samsung’s modern "One UI" interface, providing a more aesthetic and streamlined user experience. Technical Report: Next Gen OS v37 for Samsung
Technical Report: Next Gen OS v37 for Samsung Galaxy J2 (SM-J200G) April 13, 2026
Features updated wallpapers, a modernized gallery app, and a new lock screen style. 4. Installation Requirements