How do I fix flickering issue on Apple Watch Series 3?
Apple Watch Series 3 smart has flickering problem since last three days
How to resolve
[Re-Titled by Moderator]
Apple Watch Series 3, watchOS 8
Has the battery ever been replaced by Apple?
Did you check the battery health in the settings?
This could be a defective battery, at the end of the usable lifetime.
Apple Watch Service and Repair - Apple Support
Or have you been swimming lately?