"Use enough momentum so that the finger presses the string to the fingerboard in one action. Don't double-dip!"
The reason that finger-joints collapse is that they don't have enough energy in their swing to articulate the note using one finger action.
If your finger only lands on the top of the string and then presses the string to the fingerboard, you will always have a faulty finger action. The finger action should be one movement from air to fingerboard. No double-dipping!
Don't lift too high or too low. Lift only high enough to create momentum and keep the same curved finger shape in the air.
Don't hit the string too hard. Use only enough momentum to touch the string to the fingerboard....