Unfortnetly, very little hardware comes with Linux preinstalled.

If you’re getting a prebuilt (which most people do) then drivers will be preinstalled.

Linux is a combination of the Linux kernel (some really low level software that tells the OS how to communicate with your hardware, not something most users should worry about) and software from GNU (some Linux users call it GNU/Linux for this reason). This is then used as the base for distros, which are basically just that plus a package manager (how you install apps) and usually a desktop environment and default apps as well.

Theoretically yes, you could create an operating system and name it Steve, but it wouldn’t be Linux unless it had the Linux kernel and GNU software.

Edit: as others have pointed out, yes, you can technically have linux distros without GNU, but GNU-based Linux distros are by far the most popular option, so you’re highly unlikely to find a distro without GNU unless you’re hunting for one.

Pop is a fork of Ubuntu, which is a fork of Debian.

To be fair, Nvidia support on Linux has been historically quite poor, with users having to manually install drivers (something the average person shouldn’t have to think about). Though even that has gotten much better recently, with Debian now allowing forks to have proprietary drivers built in.