Sounds like the title of a gameshow.
Does neu trigger soft mutation?
Dileu is only mutated because, here, it is used as a verb noun -see ‘Tips’.
If ‘dileu’ was used in another verb form it would not be mutated - again see ‘Tips’ again.
Why is 'saving or deleting?' wrong?
I read that as Keep or Delete. What about achub?
In the context of saving a document, 'cadw' is the verb of choice. 'Achud' is more 'To save a life'/'To save someone from danger'. 'To save money' is 'Arbed'.