tl;dr:

• Qualcomm Snapdragon W5 Gen 1 SoC, 4-core CPU clocked at 1.7 Ghz, Adreno 702 GPU, more power-efficient than the previous SoC (Exynos 9110);
• Google is not using the W5+ variant, which adds the QCC5100 coprocessor, it will be using a custom coprocessor instead similar to 1st gen Pixel Watch;
• NXP SR100T UWB module (https://www.androidauthority.com/what-is-uwb-1151744/);
• 306mAh battery (vs 294mAh in 1st gen);
• Samsung Display instead of Pixel Watch’s BOE panel, specs remain the same;
• Wear OS 4 (based on Android 13) and seamless updates (https://source.android.com/docs/core/ota/ab);