So I fixed the knocking issue after servicing the hub:
wheel is turning ok
But now the chain won't go to the biggest sprocket, and it will fall through the smallest one.
I think it's related the fact that the axel is not evenly installed:
I don't have enough tools at home to re-adjust the axel, and I thought I could adjust the derailleur instead. And as usual, I made a mess
. Now the tire is rubbing on one side even more -- while maybe it was rubbing a tiny bit before.
So one step forward and two steps back.
It takes so much time to learn this stuff, lol.