Over the years I've built most kinds of decks you can name. Product and consumer decks, send-aheads, fundraising decks, training handbooks, case studies, testimonials, industry breakdowns.
Creating it all comes down to one question: how does it feel on the first scroll? If a deck looks daunting the moment someone opens it, you've already lost them, and it's rarely about length. It's the design, the format, the way the thing is laid out. I keep jargon out unless it genuinely earns its place, or unless I'm in front of a room where one shared bit of terminology makes everyone's life easier.
I love the design side. I'm not a trained designer, but I've gotten good at borrowing assets and styles from work I admire and keeping only what fits the situation in front of me.

My process is simple, and it's usually always in this order.
The order is the whole point. Most bad decks happen because someone starts at step three, with slides and content, before they've decided what the thing is even for.