“Slide deck” is an old person term, not a young person term.
If anything calling it a slide deck makes you sound old.
It’s like calling your remote a “clicker”. A term that is still used but only by the old crowd.
Both “clicker” and “slide deck” made a resurgence, these are definitely not exclusively old terms.
My experience the last few years is that being old makes everything you say sound old.
For sure especially anything related to technological advancements.
Slide deck refers to the old film projectors, which no one uses anymore except old people. So of course youngsters will have zero clue what a slide deck is. There is no use for this term anymore and it’s dying along with its technology.