A bit of a pause due to life getting in the way but I'm now able to get back to setting up this device.

Got a cheap SSD to try my luck and see if it makes a difference, but alas it was still not detected. That's 5$ down the drain.

Next, however, I noticed that there's a bios update available from lenovo - 1.58. There's nothing about SSD/pcie/nvme in the release notes but I decided to try it anyway. Lo and behold - the nvme is now visible when booting from the arch iso. Perhaps folks at lenovo heard my plea and decided to fix it up. Or maybe it's just something random, who knows. Regadless, I am now able to continue the linux on arm quest this weekend. Looking forward to it.

As a side note, when looking up how to open the laptop up I noticed that my version has an extra heatsink on the SSD. Perhaps my exact model is a bit special?