The knob itself will either have a hole on the side(sometimes they have two) where you’ll need to loosen a setscrew or it’d be pushed on.
The setscrews are typically an Allen head or a flat head(slotted) screw, if you don’t see any holes on the side then it’s safe to assume it’s pushed on and you can use something to carefully pry it off.
The potentiometer will most likely have a nut under the knob securing it to the housing.
Yes it’s probably a friction fit.
They can be tough to get off sometimes but I’ve had success by carefully prying them off if you can’t get it by pulling on it.
If it was mounted to something with a nice finish or not metal I’d approach it differently but that doesn’t seem to be an issue here.