すら is identical.
Negative: taking for granted not the case
In a sentence with negative form (〜ない), it shows that something taken for granted is not the case. "not even close" to show that not even the minimum expectation has been met.
宿題が多すぎて、トイレに行く時間さえなかった There was so much homework, I didn't even have time to go to the toilet. (You'd think you would have time to go to the toilet right?)
お弁当を買うお金さえなかった。 I didn't even have money to buy lunch...
A sentence that combines the negative and the 〜ば shows that the negative meaning takes precedence.
自分の過ちを認めさえしなければ、問題は解決しないよ。 The problem won't be solved if you don't even acknowledge your own mistakes, you know.
さえ〜ば
For sentences that are not in the negative, it can also be like 'that's all you need to get there! Nothing more!' Almost all of these sentences I have found use this together with さえ(...)〜ば. I think this might mean that it requires this structure for a positive sentence?
お金さえあれば、何でもできるよ。 As long as you have got money, you can do everything!
そんなにほっておいてさえいたら、直ぐ直るよ。 You just have to leave it like that, and then it will settle itself!
It isverb〜 , taking the i-stem.
ビタミンを==食べさえすれば==、健康が保証されますよ。
で
Add a で tonoun＋ to make it sound more empathetic. Purely stylistic.
天才でさえ出来ないのに、あなたが出来るわけがないでしょう If even a genius can't do it, there is no way you can do it.
私でさえ出来れば、あんたには楽ちんでしょう。 If even I can do it, it should be a breeze for you.
bunpro さえ http://www.guidetojapanese.org/even.html jlptsensei.com - さえ〜ば