For many experienced Linux users, Debian is the best Linux distribution a person can choose. Debian is a Linux distribution that has been around for almost 30 years, making it one of the oldest and also most well-known Linux variants available. Ubuntu Linux is a fork (derivative) of Debian and is therefore younger. But also Kali Linux, Raspbian, Knoppix, Zorin OS, elementary OS and many more variants are descendants of Debian.
Debian is a very conservative distro and has a very open and non-commercial mindset. Everything is 100% open source by default. The disadvantage of being conservative is that one has to wait a bit longer for kernel updates and thus drivers for new hardware.