Taiwan's Phison is known for its flash NAND controllers, and have been going strong for the past three years. They have unveiled a road map for SSD controllers that support PCI Express Gen4. One model jumps out the PS5018-E18. 

This “PS5018-E18” controller which will be shipped to customers in the second quarter of 2020 is based on a Cortex-R5 ×3, processor design and is fabbed at TSMC 12nm. By bringing this controller towards NVMe revision 1.4 the transfer rate per channel has increased from 800MT/s towards 1200 Increased to MT/s. And when you math that, that means a maximum transfer speed of roughly 7GB/s for both sequential reads and writes. Here's a nice value as well, random read/write performance would be listed at 1 million IOPS, and all that with an expected peak energy consumption of 3W.