The problem is MS cheaped out on XBOX ONE. The southbridge chip has SATA 2 interface, and eMMC 4.5 spec.
SATA3 was already a thing for a couple years when Xbox ONE launched. MS didn't update the Southbridge in 2016 for the ONE S, nor did they upgrade for the 'high performance' ONE X in 2017.
So XBOX ONE is living circa 2009...
Now SATA2 can do up to 375MB/s but even replacing the internal drive only shaves a few seconds off boot and load times versus the spinning drive's impressive 40MB/s.
So there is something drastically screwed up with the X1 subsystems. Because 375MB/s would actually be pretty damn good in comparison.
Part of the problem may be the eMMC 4.5 standard for the built in NAND cache. Only 52MHz (not sure if X1 supports DDR mode for a massive 90MB/s transfer speed). The OS is the only thing that can use the eMMC, and that is where the OS is cached. Which explains why even an internal SSD does almost nothing for boot times.
eMMC 5.0 was just around the corner with 200MHz when X1 came out. But Microsoft didn't update the southbridge for X1S or X1X.
A console should be near instant on, not take almost a minute just to boot to the dashboard. 300MB/s read speeds would be appropriate. Probably would be about 15 second or less boot time.
MS and Xbox are trash.