nvme drives, SSD drives connected via PCI Express, are getting more common becasue they can be faster than SSD drives connected via SATA.
I installed such drive, an m2 stick via a PCI Express card into my workstation, a Lenovo Thinkstation C30, that I bought second hand (refurbished). This solution [with an m2 stick via a PCI Express card] is much cheaper than buying a computer that is new enough to boot from nvme.
In this configuration it is not possible to boot directly into the nvme drive. The BIOS/UEFI system does not recognize it. But using Ubiquity in Xubuntu Focal I can make a boot partition in a SATA drive and from there boot into the root partition in the nvme drive. I can also run sudo update-grub from my main operating system in the SATA-SSD to get a working menuentry.
I tested the installer Calamares of Lubuntu Focal. It does not recognize the nvme partition, and I did not see any [intuitive?] way to put the boot partition in another drive and the root partition in the nvme drive. Maybe there is a way, but direct testing in a computer that can boot from nvme is much better.
Call for help to test installing into an nvme drive
So if you have a computer, that can boot from an nvme drive, and you can it use for testing (including editing and/or overwriting the nvme drive), please let me know, and we can talk about details of the testing.