Windows does not allow third-party themes by default. Use UltraUXThemePatcher to "patch" your system, allowing you to copy Mac-style .theme files into your C:\Windows\Resources\Themes folder. The Icon Pack: 7TSP

: An all-in-one installer designed to automate the visual overhaul, including the dock and shell styles. SkinPacks - Big Sur Skin Pack Essential Customization Tools

Many packs allow you to toggle specific features, like choosing between Light and Dark modes.