Ubuntu or Kubuntu

Sup guys i recently started using Linux OS's and i saw that Ubuntu has different flavors you can choose
and i started to research on each one i found Ubuntu and Kubuntu very interesting but i need some input
from you guys and see from your experience and perspective which flavor is i guess you can say better
and to make it easier i will have some simple requirement questions that you guys can answer so it can
help us get a better/accurate view on which flavors fits the most.

I have 4 GB of RAM which flavor runs fast on boot and while in use?

Which flavor has better gaming compatibility because i use steam?

I am also going onto the path of becoming a pentester and doing all that hacking stuff which flavor is better for that environment?
(Do not worry i am not going to use the hacking for bad i live in Las Vegas so i'm looking into stuff like IT, Defcon, and Hackathons)

I will also being doing coding like Python, HTML, PHP, Perl, etc. Which flavor takes that kind of environment?

Which flavor has more security?
(I mean in like firewalls and etc)

Sometimes i like to do usb tethering with my android, which flavor is good for that type of use?

If i'm not gaming or doing hacking stuff sometimes i like to sit back and watch movies, read e-books,
and make images (Like Photoshop), which flavor is good for that environment?

I like to multi-task to get more things done faster, which flavor is good for that?

Which flavor is good when it comes to using VPN's and Proxies?