How much space does a pet rabbit need?

Your whole house. And garden. Kidding.
They do not need huge amounts of space but must NEVER be locked in a cage as they are very active animals that like to run, jump and play. Start with a room if you can, or at least a sectioned off part of a room. See video below.
Since they are prey animals they should in a perfect world be inside your house, cottage, or flat as the smallest thing could scare them
If they are outside, they need enough shade, water, food and hidey-holes to hide out under when those ridiculous hadedas fly over.
They need to be safe from cats, genets, owls and eagles. (And in Joburg in 2023 apparently from tigers.)
Their hidey-holes/cover must provide deep shade as the African sun is hectic. Do you remember standing on that athletics field on a midday?