Re-enable (some) keyboard controls, after disabling YT defaults using uBlock Origin. This prevents time scrubing when switching tabs using Alt+1-9.

make-yt-great-again.js

// ==UserScript==
// @name         Re-enable YouTube keyboard controls
// @namespace    com.cesalazar.ytkbctrl
// @version      0.8
// @description  Re-enable (some) keyboard controls, after disabling YT defaults using uBlock Origin.
// @author       Carlos E. Salazar
// @match        https://www.youtube.com/*
// @grant        none
// ==/UserScript==

// Prevent seeking time with the keys 1-9 by adding this line in uBlock Origin, under `My filters`:
// youtube.com##+js(addEventListener-defuser.js, keydown)

(function() {
  'use strict'

  const simulateClick = (el) => el && el.dispatchEvent(new MouseEvent('click'))

  const targetIsInput = ({ target }) => target && target.nodeName === 'INPUT'

  const video = document.querySelector('video')

  // Specific to the control buttons of the player
  const getButton = (name) => document.querySelector(`.ytp-${name}-button`)

  const mappings = {
    KeyF: getButton('fullscreen'),
    KeyI: getButton('miniplayer'),
    KeyK: getButton('play'),
    KeyM: getButton('mute'),
    KeyN: getButton('next'),
    KeyP: getButton('prev'),
    KeyT: getButton('size'),
    Space: getButton('play'),
  }

  // Little dance to toggle the miniplayer on and off
  let isMiniplayerActive = false
  const toggleMiniplayerButton = () => {
    mappings.KeyI = getButton(
      isMiniplayerActive ? 'miniplayer-expand-watch-page' : 'miniplayer'
    )
    isMiniplayerActive = !isMiniplayerActive
  }

  document.addEventListener('keypress', (event) => {
    if (targetIsInput(event)) return
    event.preventDefault()
    const { code } = event
    if (code === 'KeyI') toggleMiniplayerButton()
    return simulateClick(mappings[code])
  })

  document.addEventListener('keyup', (event) => {
    if (targetIsInput(event)) return
    event.preventDefault()
    switch (event.code) {
      case 'ArrowLeft':
        video.currentTime -= 1
        break
      case 'ArrowRight':
        video.currentTime += 1
        break
      case 'KeyH':
        video.currentTime -= 10
        break
      case 'KeyL':
        video.currentTime += 10
        break
    }
  })
})()