Regarding updating NVME drives.
Samsung and Western Digital have windows tools that do it.
As you now have Linux installed, this page on how to do firmware upgrades on WD devices might here:
It might be just one of the NVME drives that has problems with suspend. Can you try connecting one at a time, to see which might be the problem one.
But based on other threads, the SN7100 seems to have caused problems in the past, so maybe try updating that one first.
Unfortunately, it looks like the SN7100 4TB you have is a SANDISK product, and not a WD one, so might have a different method to update its firmware than on the link above.
The latest firmware for the SN7100 appears to be: 7615M0WD.fluf
So, see if you already have the latest firmware or not with:
cat /sys/class/nvme/nvme0/model
cat /sys/class/nvme/nvme0/firmware_rev
cat /sys/class/nvme/nvme1/model
cat /sys/class/nvme/nvme1/firmware_rev