The Sony Xperia 1 III has only recently been officially launched and there is already a rumor about the next model in the flagship Xperia 1 line. The details about the potential Sony Xperia 1 IV (mark 4) smartphone concern the camera hardware and are at least based on reason if not necessarily fact.
https://www.notebookcheck.net/Early-Sony-Xperia-1-IV-rumor-focuses-on-the-potential-camera-equipment-provider.541167.0.html
No idea why they used Samsung in the first place since most Samsung mobile sensors were designed with an original Sony in mind.
Good. Xperia selfie cameras are terrible.
Work on the software too, it isn't only about the hardware.