samsung is actually updating a device that is around five years old??? according to egadget, they are updating to improve battery life and possibly a new UI. I am still using gear s2 classic and without the update, battery still lasts a little over 24 hours. Just check to see if the update is available for me and its not.
https://www.engadget.com/2020/02/03/samsung-updates-gear-s2/
https://www.engadget.com/2020/02/03/samsung-updates-gear-s2/