This script will revert all UI changes prior to late 2022 (which disables rounded corners on everything and reverts 2019-2022 backgrounds.)
< Rückmeldungen auf YouTube - Revert UI changes before late-2022 (Non-Rounded Design)
Same here. Looks like YT updated again.
But, this one does work https://greatest.deepsurf.us/en/scripts/459222-youtube-non-rounded-design-legacy-version due to lacks JavaScript ES11 support
Seems like the Subscribe button dissapeared again