Hi @rob215x
Frankly, I don’t know why CloneZilla would not list your NVMe device in disk to disk mode; unless it wasn’t configured properly in BIOS; which is unlikely if you can see partitions in partition to partition mode.
It’s hard to know without seeing through your eyes.
However, I have just created a walkthrough (of sorts) which you might like to use as a guide.
I hope it helps. Cheers.