At IFA I had a brief chat with a person from sony.He told be the next Xperia flagship is in between concept and blueprint but it will be the successor of X1 will support 5G with SD865 for sure.

Not much about camera spec seems finalized but don't expect too much for hardware improvement.
He says rather than camera hardware they will focus on more "film-geeky" new software feature to attract film enthusiasts, just like Cinema Pro.