If you need different kernel or firmware (you should not, but in the unlikely event...) you put it on a separate USB drive. You need two drives, and two ports on the computer, at least with a LiveDVD/USB, which is read-only. The NUC has multiple ports. You could also use the SD card reader which is built in. To install the kernel or firmware, use dpkg.
That works from a recovery terminal if the desktop won't load. But once again, with an 8th gen CPU, it shouldn't be necessary.

All I know about the device you posted is what the website showed, which is that Windows 10 comes installed. If you have other details, fine. I have avoided paying the Microsoft tax for 20 years or so, and that's easy to do by buying a kit, with the storage and memory bought separately. If that's the way you're doing it, good on you. If not, it's your money.

Good morning,

What I intend buying is this, not sure what link I provided earlier. It is a barebone with RAM and storage ordered on top of that, so - no OS.

How do I know what Kernel, what firmware? where to get it? I want to have it ready before starting the installation, just in case.... Yes, it has multiple USB ports, the one with the single port is my Microsoft Surface 3 Laptop - what will I do in this case?

Have a good day
Alex

It depends on what distro you plan to install. If you're installing Ubuntu 20-something, it should be fine. Ubuntu takes Debian Unstable, tweaks it until it barely runs, and shoves it out the door. The only thing that I would foresee possible problems with is Debian Stable, which still has the 4 series kernel. As for a Microsoft Surface, I have no clue. I've never seen one. I suggest you just run the installer and see what happens. If it won't boot to a desktop, come back, and be prepared to show your work, exactly what you did and how, and the exact results, so we don't have tu guess. But I think it should install and run without serious issues.