That's a spring hinge - I would not attempt to disassemble it. For this one, I'd use a light oil, like 3 in one oil or sewing machine oil and just do my best to get it into the hinge, either through the upper hole with the bar coming out of it, or allowing it to penetrate down the seam in the center of the top. You'll probably need to work the door back and forth a bunch to get the oil where it needs to go.

Like others have said. Silicone spray is magic. Put a paper towel on the ground underneath it, spray the gaps a little, nove the door back and forth. Repeat a few times. Clean the outside afterward by wiping the excess.

I would use a spray lubricant with silicone in it. A Teflon one will work too but Teflon is horrible for the environment so I avoid them. Something like this

https://www.homedepot.com/p/Blaster-11-oz-Industrial-Strength-Silicone-Lubricant-Spray-16-SL/202529794

Or you could use a gun oil and squirter a couple drops on it.

3-in-1 in the gaps might help. That hole on the top might do it?

I use white lithium grease (spray bottle with thin straw) in the hinges. Maybe you can find a way into the inside with the straw. WD-40 and similar oils are too thin for a hinge long-term.

That's a weird one! Can you press that little pin in and push from the bottom?