A functional requirement says what a user can do. A nonfunctional requirement says how that behavior must perform or what it must preserve. "Upload a photo" is functional. "A successful upload survives one disk failure" is a durability requirement. Keep both visible, because a fast upload that disappears doesn't meet the brief.
Turn adjectives into testable targets. "Fast" might become a response within 200 milliseconds for 95% of reads, measured at the service boundary. Ask what happens outside that percentile and during a dependency failure. Availability, durability and latency describe different things. Scope also needs exclusions: if payment collection is out of scope, adding it increases work without answering the problem. Choose the requirements for each fictional service and leave the distractors out.