Difference between 「～てからでないと」and 「～ないことには」

Question

Both of these grammar can be translated to English as

A～てからでないと/～ないことにはB = Unless A is done, cannot do B

From what I can find,

～てからでないと stresses the order or sequence of actions, that until A is done, B will not happen

～ないことには stress the requirements of the action, that A must be a condition that is satisfied, in order to do B

However I'm still not confident if these nuances are accurate, and I cannot distinguish its usage in certain sentences.

1) きちんと勉強してからでないと、いい仕事を見つけられない。(until you study?)

2) きちんと勉強しないことには、いい仕事を見つけられない。(if you don't do the action of studying?)

Unless you study, you can't find a good job.

3) 塩は砂糖をいれてからでないと、甘みが野菜に染み込まないよ。(until you add sugar to the salt)

4) 塩は砂糖をいれないことには甘みが野菜に染み込まないよ。(if you don't add sugar to the salt)

Unless you add sugar to the salt, the vegetables will not absorb its sweetness.

Can someone please tell me if I'm understanding this correctly, and are they interchangeable in all cases?

Answer 1

～てからでないと/～ないことには = Unless A is done, cannot do B

1. ～てからでないと - After 〜 is complete.
2. 〜ないことには - Before someone starts doing 〜.

When no one knows what's going on at the end and things are happening or sure it will happen, in these case we use #1. In other word, "Let the things done first!"
「終わったらわかる」

When the one doesn't start doing or even not trying, the thing won't start anyway, in these case we use #2. In other words, "Let the things begin anyway!"
「始めたらわかる」