If you are looking for real operating systems known for extreme privacy, security, or "dark" aesthetics (similar to the fictional Blackwin), these are the top contenders used by professionals:
It offers unparalleled tool variety but is recommended for advanced users familiar with Linux. blackwin os alternative
To help narrow down the perfect match for your specific hardware, let me know: What is the of your computer? If you are looking for real operating systems
What are the of the machine? (specifically the CPU and RAM amount) and unnecessary system services.
Developed by NTDEV, Tiny11 (based on Windows 11) and Tiny10 (based on Windows 10) are meticulously stripped-down versions of the standard Microsoft OS. They remove telemetry, bloatware, and unnecessary system services.