rmfnla

You have two elements that need to be separated to be properly diagnosed:

Unattach the cable and work the shifter while pulling the cable end with your hand; you should be able to detewrmine if the cable moves freely or gets hung up.

Work the derailleur with no cable attached. For best results remove the chain, too. All you want to do is make sure it moves through its travel without any hitches.

FDs are not designed to be overhauled. A good soaking in solvent followed up with a light lube job is usually all they need unless they are worn out (which yours should not be in only one year).