If you have PS Plus you can put saves in the clouds, but if you joined it after the save was made it won't auto upload it so you need to go in to the PS4 settings and chose which ones to upload. You can also do a transfer from your PS4 on wifi or LAN.
Personally I've got Mile Morales and Demon's Souls here so those will go first.
It's not much effort, I did the same with the incoming PS5. Bought a PS Plus subscription and uploaded the saves that I'm likely to use again but otherwise I want a fresh machine so not bothered by the whole PS4 transfer thing.
If you have PS Plus you can put saves in the clouds, but if you joined it after the save was made it won't auto upload it so you need to go in to the PS4 settings and chose which ones to upload. You can also do a transfer from your PS4 on wifi or LAN.
Personally I've got Mile Morales and Demon's Souls here so those will go first.