I think you are confusing relaxed with flaccid.
Having the fingers fall a little higher than the last is actually the natural way your fingers will fall. That doesn’t create tension. In the first link pictures 3, 4, and 5 are good examples of what it means to have tense or locked fingers.
Of course there is some tension. Without it your fingers would just be hanging there unable to do anything. But you don’t want your hands to look like you are making a claw of or them, or have the fingers pushed back so that the joints are hyper extending back, particularly the joint at the tip of the fingers.
Your fingers should curve constantly all the way to the tip so that when you pluck your finger tips aren’t flopping back like a weak plectrum. That doesn’t produce good tone, and it also throws off timing since the string ends up being released whenever you reach the give point of your joint rather than at the moment you choose when moving the finger in the first place.
The fingers have to be one above the other so that they don’t get in each other’s way. If they are all on the same plane across the strings then when you pull them back you will be pulling them into each other.
You should try to pull the fingers flat in to the palms, and the thumb down over the knuckle of the pointer finger, as much as possible.
Of course there are times when you are playing a fast and difficult passage where it is impossible to get