When large games are shared or downloaded from unofficial sources, they are often split into smaller "parts" (like .part1.rar, .part2.rar, etc.) to make the transfer more manageable.
Files with these naming conventions are typically found on third-party file-sharing sites rather than official storefronts. Using such files carries significant risks: Crash.Bandicoot.N.Sane.Trilogy.part4.rar
For the best performance, including 4K support and 60 FPS gameplay, you should download the game through official digital retailers: When large games are shared or downloaded from