What's the difference between 上で and 次第？


I was wondering what was the difference between 上で and 次第. As for their
significance I think that they differ a little. On one end, 上で bears the
meaning of "upon doing something", whilst 次第 implies that "as soon something
it's done, also something else can be done". There are are differences that I
have overseen? May I also add that I'm not sure whether to use 上で and てから？




Xした上で{うえで} Yをする implies you are required to do X before doing Y. The following
sentences from [goo辞書](https://dictionary.goo.ne.jp/thsrs/17265/meaning/m0u/)
:

> 予約の時間を確認のうえご来店ください
[code]

    Please come to our shop after making sure your reservation time.
    
[/code]

> もう一度診断をしたうえで、手術の日時を決めることにしよう

`Let's decide the date of the operation based on another diagnosis.`

X次第でYをする describes the situation of X will occur Y. My example sentence is
following :

> 2人の選手の試合結果次第で、オリンピックに行けるかどうか決まる。
[code]

    Depends on the result of two players' match, it decides whether you can go Olympic Games or not.
    
[/code]

~てから can be interchangeble with 上で in informal.

