I just added this to my userstyle CSS for YouTube:

  /* Remove pink tint from end of progress bar */
  .ytp-play-progress.ytp-swatch-background-color,
  .style-scope.ytd-thumbnail-overlay-resume-playback-renderer,
  .ytp-scrubber-button.ytp-swatch-background-color {
      background: var(--yt-spec-static-brand-red) !important;
  }