Also when/how do you get the Namekian awakening power? THe giant shit?
You need to talk to Nail in the Namekian Time Rift (if it's open for you, if it's not yet it means you need to progress the story some more). You will need to defend Guru's House and once you've done it 6 times (there's 6 quests) you will be prompted to learn the awakening from Nail. Do it a second 6 times and you will get a special item needed to get the alternate ending.
Please enjoy getting infinite comboed because you dared playing a melee character instead of a bullshit beam spam character, and Frieza can literally grab you instantly from melee range, or tail slap the second you get behind him, and then combo you to death.
Sounds to me like you're severely underleveled. Though, the AI there for some reason is really smart. Regardless, you have plenty of avenues to level up from so I'd suggest you stop trying to brute force it like you are and level up through doing mentors/advancement tests or PQs.
I was level 30 for that story mission and they were real pushovers. I'm also a melee build. They aren't punishing you at all, it's your level.
Knock em down advanced seems impossible for me, when I fly behind the enemy before the last input the enemy stops halfway on the way to me when I knocked him away.
It's a three frame window. You need to be really quick otherwise they will roll out. Rolling out signifies you're too slow. It's literally the only thing in the game's combat system that requires any sort of execution from a fighting game standpoint.
At what point can you be in a hub world with other folks running around?
Around after you've done the first or second story mission on Namek, I believe.