It seems that Sony has at least two new Xperia smartphones in the works. According to some sleuthing by @NodSikharulidze, the Japanese company is developing one smartphone with an SM6350 chipset and another with the SM8350. Qualcomm has already confirmed that the SM6350 is the model number of the Snapdragon 690, while the company is thought to have assigned SM8350 to the Snapdragon 875.
Android Next and GSMArena believe that Sony is preparing an Xperia 10 III with the Snapdragon 690, along with an Xperia 1 III using the Snapdragon 875. This belief seemingly stems from Sony having released the Xperia 10 II and Xperia 1 II in February, so the thinking goes that successors should be arriving sometime around February 2021.
Either way, the Snapdragon 690 seems like an odd choice when other OEMs are using the Snapdragon 750G for their mid-range smartphones. The Snapdragon 750G has a 10% higher clock speed than the Snapdragon 690 does, for example, along with a 14% higher memory bandwidth. The Snapdragon 750G also has a slightly faster modem than the Snapdragon 690 does, along with an improved instruction set.
The appearance of the Snapdragon 875 in a flagship Xperia smartphone should not raise any eyebrows, though. We would expect Sony to release a successor to the Xperia L4 too, if it plans to repeat its 2020 roadmap.