Give it a try, experiment with -crf and bitrate values, and you’ll quickly find the sweet spot for
# Second pass (actual encode) ffmpeg -i "$SOURCE" \ -c:v libvpx-vp9 -b:v 4M -crf 30 -pass 2 \ -c:a libopus -b:a 128k \ -metadata title="Young Sheldon – S06E15 – A Patch of Light" \ -metadata artist="CBS Studios" \ -metadata genre="Comedy" \ -metadata date="2023" \ "Young Sheldon S06E15 - A Patch of Light.webm" young sheldon s06e15 libvpx