As a uBlock Origin filter (paste in Settings > My Filters):

  ! No CSS animations
  ##*,::before,::after:style(transition:none !important;animation-delay:0ms !important;animation-duration:0ms !important)
  
  ! No CSS animations (different method)
  ##*,::before,::after:style(animation-timing-function:step-start !important;transition-timing-function:step-start !important)

There's other (often perf heavy) CSS clutter that's nice to get rid of:

  ! No image filters
  ##*,::before,::after:style(filter:none !important)
  
  ! No text-shadow
  ##*,::before,::after:style(text-shadow:none !important)
  
  ! No box-shadow
  ##*,::before,::after:style(box-shadow:none !important)

  ! No rounded corners
  ##*,::before,::after:style(border-radius:0px !important)

No rounded corners is fun. You realize many loading spinners are actually CSS rounded corners! Youtube becomes almost unrecognizable — mercifully — especially if you also revert the new TikTok-inspired font:

  ! Un-bold Youtube
  youtube.com##*:style(font-weight:400 !important)