Use this and all's well, presumably (7)

I believe the answer is:

cureall

I'm a little stuck... Click here to teach me more about this clue!

'well presumably' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'use this and all's' is the wordplay.
'use' becomes 'cure' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'this and' is a charade indicator (letters next to each other).
'cure'+'all'='CUREALL'

Can you help me to learn more?

I've seen this clue in The Guardian and The Irish News.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.