Do the following steps to turn a PS4 game of 50 GB into a working dump of 1 GB.
1) Create a game that is only 1GB in size
2) Add unnecessary files to it until it adds up to 50 GB
3) Get Sony to allow you to release your game on the PS4
4) Dump the game
5) Rip out all the unnecessary files you added in step 2
There's another way to turn any huge PS4 game into 1 GB.
1) Take the .pkg of your game that is larger than 1 GB and open it in a hex editor of your choice
2) Navigate to 0x40000000
3) Select all the bytes including and following the address mentioned in step 3
4) Hit the del key on your keyboard and if there's a prompt coming up, confirm it
5) Save the results
This leaves you with a file of exactly 1 GB. It's not functional at all, but I didn't find anything in the OP about this being a requirement.