OK, you really really really really have to want to do this, and you can't do it with a picture already saved, or even a screenshot. You
have to do it while you're using the camera. Take your picture at high resolution. It can be scapes or from a replay. Once you have the picture and are looking at it, zoom all the way in. Move to the top left, share button, triangle. Move to top center, share button, triangle. Top right, same thing. Repeat across the center of the image, then across the bottom of the image. You have 9 screen shots. You might be able to cover the image with just two passes across, but more overlap makes compositing easier.
Go to Library, Capture Gallery. Pull each one up and save it to USB.
Take the USB to your PC or Mac, Open all the files in Photoshop (or something) and crop them to remove any black borders, the control button prompts at the bottom, and so on. Save each crop.
The easiest thing now is to do a File, Automate, Photomerge in Photoshop, pick the collage format. (I actually ended up with a couple of bad seams in the overlaps, so I manually built the composite. A bit more work.)
This is the Pig at Flugplazt, 3804x2140, from a PS4. Click the image and zoom in.