unfollow-all.js

async function run() {
  const wait = ms => new Promise(resolve => setTimeout(resolve, ms))

  const selector = 'div[aria-label="Toggle to follow"] div'
  const nodes = [...document.querySelectorAll(selector)]  

  if (!nodes.length) return
  
  for (let node of nodes) {
    const text = node.parentElement.parentElement.parentElement.innerText
    console.log(text)

    if (!text.includes('Following')) {    
      // Remove Unfollowed node so that it will save some RAM
      node.parentElement.parentElement.parentElement.parentElement.parentElement.remove()
      continue
    }

    node.click()

    await wait(100)
  }
  
  // Run again until no entries left
  run()
}

// Click on the arrow on the upper right > settings and privacy > news feed preferences > unfollow > run this code on DevTools

run()