Browser will scroll down, upvote all items and reload the page.

hacktheplanet.js

// Go to a profile, open javascript console (cmd + alt + j) and paste the following code 
// or you can save it in handy snippet https://developers.google.com/web/tools/chrome-devtools/javascript/snippets

// Update this selectors as LinkedIn's layout is updated
const endorseBtnSelector = '.pv-skill-entity__featured-endorse-button-shared';
const openSkillsSectionBtnSelector = '.pv-skills-section__additional-skills';

const body = document.body,
  html = document.documentElement;
const height = Math.max(body.scrollHeight, body.offsetHeight,
  html.clientHeight, html.scrollHeight,
  html.offsetHeight);

const somethingWrongTimer = setTimeout(() => {
  alert(`hacktheplanet: 🤔 Something went wrong with this profile. Maybe it hasn't got any skill posted? Try scrolling to the skills section and running this script again. Reloading the page...`);
  location.reload()
}, 5000)

let openSkillsSectionBtn;
(function scrollAndClick() {
  if (!openSkillsSectionBtn) {
    window.scrollTo(0, height / 2)
    setTimeout(() => {
      openSkillsSectionBtn = document.querySelector(openSkillsSectionBtnSelector)
      scrollAndClick()
    }, 300)
  } else {
    openSkillsSectionBtn.click()
    const btns = document.querySelectorAll(endorseBtnSelector);
    if (btns.length === 0) {
      alert(`hacktheplanet: ❌❌❌ Nothing available to upvote. Maybe the skills are already upvoted or you can't access skills from this profile. Reloading...`)
    } else {
      const unpressedBtns = Array.from(btns).filter(btn => btn.getAttribute('aria-pressed') !== 'true')

      if (unpressedBtns.length === 0) {
         alert(`hacktheplanet: ✅ Every skill in this profile seems to have been endorsed. Reloading...`)
      } else {
        let votedCounter = 0;
        for (let btn of unpressedBtns) {
          if (btn.getAttribute('aria-pressed') !== 'true') {
            btn.click();
            votedCounter++;
          }
        }
        alert(`hacktheplanet: ✅✅✅ ${votedCounter} skills upvoted! Reloading...`)
      }
    }
    clearTimeout(somethingWrongTimer)
    setTimeout(() => location.reload(), 3000)
  }
})()