Neither one, I don't understand why people seem to think windows or linux are the only operating systems,
I have never used Windows, never considered it to be a operating system, I do remember when it was first released,
and I even tried it, but it was really a very bad program and crashed my system, I just stayed with Dos, and went to
FreeDos, when it was released.
For servers , Unix, and later Linux, not only as a server but on my PC as well, after all said and done though, I am using OpenBsd, both on the desktop PC and on one server, the other server is still Linux, but will be migrating / changing it
to OpenBsd soon.
Never had any use for MS windows, never could do anything with it. However I do think it is important for anyone to use
the OS they are most comfortable with.
Since I never really used Windows, I am not at all comfortable with it, can not figure out how to do anything, etc.
On a unix or unix like system , it is user friendly and easy for me to understand.
I don't know about "kali", I have heard of it, it is another linux distro. I don't think it is intended for "desktop" use, and
I have never heard of it being used to power a server.