Another legitimately great strategy is the Wally Deflector (hate that Dilbert's creator turned out to be an asshat). Force them to do some work. Anything really works, just something to slow down the firehose and enforce that it's a partnership working towards a solution. Usually the best way is to just ask for clarification and actual hard requirements.

So many things just shrivel up and die when the person asking for it realizes IT isn't going to just outsource their full responsibilities including domain specific knowledge or basic fucking thought for them just because it's going to become digital or automated.

That's why I send "summary" emails, even if the brass tells me not to, for in person discussions