LMDE, MX, Ubuntu etc are based on Debian. Mint is based on Ubuntu, so Debian. Chimera/Endeavour are based on Arch, etc.
In the linux world, you have a linux kernel, systemd or init, a bunch of gnu utils, a window system like X or Wayland, whatever DE you want (Xfce, gnome, kde, name it) and a packaging system (apt, yum, pacman), but for me, it’s all the same.
If you want something different, try a BSD distro then? FreeBSD, OpenBSD, GhostBSD, etc
Using un*x since the 90s, this is all I know. I like awk but it can go fucking complicated, I once maintain a 5000 lines script that was parsing csv to generate JavaScript…
Yes, both are well known and (even if sometimes some people says they have lemons, for both bands) pretty solid, mine is 14 months old and runs 8h/day as my work PC
In windows, save the recovery key (to an external USB key for instance), it is a text file. Then in Linux double click the partition in Thunar or your file manager and it will ask you for the key.