there is stretching on the fingers and would like feedback on how to reduce that.
My initial feedback would be
‘You should include your blend file (or link) in your post’
To improve your unwrap, ensure you have applied your object scale and position the seams correctly. Without the blend file, the latter is more difficult you advise you
As you can see in your unwrap the scale of the finger do not match the rest of the hand.
Is it not as good without your pinning ?
Have you tried the minimise stretch option ?
What Richard said about applying scale. Also sometime when you have a tight curve like that, its necessary to make “relief cuts” to get it to lay totally flat and undistorted.
Are you trying to unwrap to match a photo skin texture? Or unwrapping for texture painting?