Ps4 pro is 4,2 Teraflops so 8,3 is about 2x, it will probably be slightly above 8,3 it's a rounding number dude. confirmation.
So you don't expect efficiency to change at all? So you expect the Playstation 5 to be as efficient as a base Xbox One on a per-flop basis? Wow.
Keep in mind this is speculation, but yes, PS5 will have 8 Teraflops at the price $400, Xbox lockhart 4TF (disc-less) at $300 and xbox anaconda 12TF at $500. They will all have 1TB NVMe/SSD drive (ultra super-fast storage) and 8core zen2 CPU and will be released in fall 2020. This is 100% certain.
You can't say it is speculation with one hand and assert something as definitive with another.
You actually have no idea what the hardware is going to be capable of, it hasn't been revealed yet.