You do not need to extract each file individually. Modern archive tools handle the entire sequence automatically.
Use a high-quality extractor like 7-Zip or WinRAR. game-cyberpunk.2077.game-(61835).part126.rar
The name indicates that this is of a larger set. To successfully extract the game, you cannot use this file alone. You do not need to extract each file individually
You must have every single part in the sequence (e.g., part1 through part126 and beyond) saved in the same folder on your computer. game-cyberpunk.2077.game-(61835).part126.rar
Put part1.rar , part2.rar ... all the way to part126.rar and any subsequent parts into one dedicated folder.