Supabase only returns 1000 rows even with .limit(5000)

Not a plan thing. The API has a Max rows setting (default 1000) that caps every response, regardless of what you ask for. You can raise it under the Data API settings, but for an export I'd paginate instead:

const pageSize = 1000
let all = []
for (let from = 0; ; from += pageSize) {
  const { data, error } = await supabase
    .from('orders').select('*')
    .order('id')
    .range(from, from + pageSize - 1)
  if (error) throw error
  all = all.concat(data)
  if (data.length < pageSize) break
}

The .order() matters, without a stable order pages can overlap or skip rows. Raising the max rows limit for everything also means one careless query can pull your whole table into a browser.