Digitimes doesn’t mention the type of controllers.
E18/16 or something else are purely speculation.
The only info now is from windowscentral who claims up to 2GB/sec.
A 2000 MB/s nvme would be hugely disappointing. That's not even close to the nvme performance I'd expect. They should be somewhere around 3500 MB/s read. If they're not ... well ... poopy console.