The Short Version
Leaker Instant Digital claims Apple shelved hardware changes for Watch Series 12, keeping the same design as Series 11 and focusing on battery life and watchOS 27 software updates instead.
Apple has been working on a blood glucose sensor for roughly a decade, and it still isn't ready. So this year's Apple Watch gets a new face and a speed bump instead. Betting on battery life over breakthroughs is a reasonable call when your big idea isn't finished. The watch ships; the sensor doesn't.