Lenovo ThinkPad X1 Carbon 6th generation
Overall, follow everything in the install guide with minor changes.
This laptop on older kernels will not be able to suspend to memory due to supporting S0i3 vs S3 which is suspend to RAM. Although both can be used the ACPI table, Linux doesn't think the hardware supports suspend to RAM. More about the issue can be see here. Here is also a bug about it with canonical upstream for those interested.
In order to have support for suspend to RAM, the kernel version must be 4.13 or higher.
If "mem" is listed in the output, no further action is required. Otherwise, a newer kernel version is required.
From here you can follow the kernel upgrade docs.
The NVMe drive is located at /dev/nvme0 which, as far as the install guide goes, replaces /dev/sda when it comes to partitioning.
In addition, build NVMe support into your kernel. Ensure the following two lines are in the kernel configuration.
See this post for additional troubleshooting tips.
emerge --ask sys-kernel/linux-firmware