

Distro: short for distribution. Linux is not an operating system. It’s a piece of technology (specifically something called a kernel) you can use to create an OS. Those Linux based OSs are referred to as distros. We are usually not calling them “Versions” because the Linux Kernel is also frequently seeing updates and that would just cause confusion.
Debian and Ubuntu: Popular distros. Ubuntu tends to be a bit more user friendly than Debian and was the default recommendation for new user for a long time. In recent years its popularity among enthusiasts declined because of a series of unpopular decisions, mainly the adaptation of something called snaps which is not completely open source and takes a bit more time to launch apps than alternatives. Debian on the other hand really values stability. Updates arrive less frequently than on other distros but undergo really rigorose testing.
Not necessarily. Both have their drawbacks. It takes longer for new hardware to be supported on Debian and setting up a Nvidia grafics card is more complicated