If you are using a PC emulator like Ryujinx, simply go to the top menu, select "Install Title Update", and navigate to the extracted .nsp file.
The software will automatically read part1 , call upon part2 , part3 , part4 , and so on to seamlessly stitch them back together. DOOM Eternal (NSP)(Update 1.13).part4.rar
What does your extraction program give you? If you are using a PC emulator like
Are you trying to play this on an or a hacked Nintendo Switch console ? simply go to the top menu