Since Realtek no longer lists the RTL8187 directly in its primary Windows 10 download section (which focuses on newer chips like the RTL8821CE), you must use alternative reliable sources:

The Realtek wireless chipset is legendary for its long-range capabilities, frequently found in classic high-power Wi-Fi adapters like the original Alfa AWUS036H . However, being a legacy chipset designed long before modern operating systems, finding a stable, working RTL8187 wireless driver for Windows 10 64-bit can be challenging.

ZOL is a major Chinese tech download site that offers a driver for the RTL8187B variant.