The fastest of the fastest m.2 and NVME speeds is 32 GB/s, and even top-notch components typically go for 16GB/s. There's absolutely no way a console is hitting that rate, unless they're losing all sorts of money per console.
Um...where are you getting these numbers from? There's not a single m.2 NVMe-compatible SSD out there getting anywhere
NEAR those speeds, and for the foreseeable future, as well. We are still talking NAND-based SSD's, correct? Even enterprise-level NAND-based SSDs don't hit those speeds.
Or do you mean Gb (Gigabit) when you say GB (Gigabyte)? That would be far more realistic and line up with what you're saying; there is a Gigabyte SSD on the market right now with read speeds of about 5 GB/s (40 Gbits/S).
........To answer the OP: the only option they have with a storage device achieving around 20 GB/s-25 GB/s is with 3D Xpoint PCM persistent RAM over a DRAM controller connection soldered to the board, or ReRAM spun off from 3D Xpoint with similar specs and functionality, also over a DRAM controller and soldered to the board. In both cases, you're only realistically looking at between 64GB-128GB, but this is persistent memory with speeds closer to (but not exactly; the latencies are notably much higher) DDR4 RAM, and long-term storage of NAND even when the power if off (plus having better P/E cycle performance).
So yes, that would be a big catch and it's possible Sony and even MS are doing something like this. But it's more realistically possible with 3D Xpoint at this stage; there have been no breakthroughs in ReRAM commercialization as a non-embedded part at capacities greater than a few megabytes. Hence why I said if Sony were to use ReRAM, it'd likely be an offshoot spun from 3D Xpoint as the technologies are very similar in most instances.
Even if they disappoint and don't go with persistent RAM, they could still use high-quality NAND (SLC or MLC) soldered to the motherboard as a fast cache connected to the APU on multiple PCIe 4.0 lanes, mimicking AMD's SSG GPU setup, but for even better performance (at least over the first-generation SSG GPU cards).