Despite being a Samsung-made smartwatch, it can be used with most Android smartphones without any issues.

Source: https://indianexpress.com/article/technology/tech-news-technology/samsung-galaxy-watch-4-classic-price-cut-flipkart-big-year-end-sale-9071715/

These vulnerabilities are linked to devices with the Samsung-made Exynos chip; precisely the modem which allows hackers to do remote code execution.

Source: https://indianexpress.com/article/technology/tech-news-technology/google-spotted-18-zero-day-flaws-in-samsung-exynos-chips-8506074/

The smartwatch was Google's first attempt at designing its own smartwatch that was powered by a Samsung-made Exynos 9110 SoC.

Source: https://www.gadgets360.com/wearables/news/pixel-watch-2-leaked-specifications-battery-processor-sensors-features-google-report-4081237