While official digital stores (Steam, Ubisoft Connect) do not sell "highly compressed" versions, you can legally compress the game yourself:
Obtain the compressed archive (usually a .zip, .rar, or .7z file).
The only difference is the installation method. High compression uses algorithms like LZMA2 or Brotli. You will need to allocate temporary space during installation (usually double the final size), but once unpacked, the game runs exactly like the retail DVD version.