I just beat the game and I am now level 70. I was told that I should automatically receive the mission, but no matter where I look, I can't find it. Is there any reason as to why I wouldn't get it?

For context, I'm a level 67 Jedi sentinel. According to my friend, I'm "playing the game wrong", simply because I've been modding my adaptive armor and putting points into alacrity, accuracy, and critical rating, instead of just equipping every other piece of gear I find. So, am I actually playing the game wrong, or can I continue to do what I'm doing with little to no late game consequence?

I keep seeing people zooming around at the speed of light with them and I know they're supposed to be in the legacy tab, but I can't find them anywhere.