The built-in NTFS filesystem compression is fairly limited in that it optimizes for performance over compression ratio; the more optimal compression scheme that's built-in is WOF:

https://devblogs.microsoft.com/oldnewthing/20190618-00/ https://learn.microsoft.com/en-us/windows/win32/api/wofapi/n... https://learn.microsoft.com/en-us/windows-hardware/manufactu...

It's not transparent like the filesystem compression, but it offers far more potentially beneficial compression algorithms such as LZX.