This has now been resolved by the means of a motherboard replacement.  I better buy some extended warranty.
Hello, I've been having problem free computing since I bought my M15 R7 along with a 2TB SN850 for secondary storage, but since BIOS update 1.12.0, the SN850 has been having performance deterioration until it vanishes from Windows OS upon every reboot.  Temperatures have been low 33-40c, but appears to be a length of time the drive has been on, rather than what it's doing. To rule out issues with the drive itself, I've purchased a Sabrent USB 3.2 NVME enclosure, and this has been giving 1GB/s transfers speeds with no hiccups nor disconnections. Unfortunately, I'm unable to downgrade the BIOS to 1.12.0 or lower for some reason, when the BIOS has flashed, version 1.13.2 shows. If anyone has similar issues, or knows how I can get the BIOS back down to 1.12.0 and below for verification on what started the issue, that would be great. Everything has been updated, no matter how flaky SupportAssist is, the only thing I've not tried yet is placing the 850 in the first slot, of which I will need to get Windows on to it.
m15 R7, 2nd NVME slot 2TB SN850 issue since BIOS 1.12.0