Short answer: this is "agency" UX. If you want to work in a startup, then 90% of what you're learning is useless. You're learning traditional practices that put emphasis on planning. Startups generally need to put emphasis on speed and flexibility and adaptation to change. For that, you might benefit from learning how to rapidly prototype with actual code and when creating UX documents, stick to what you know is important and necessary and cutout 90% of the bloat that traditional UX people design for.