This script will revert all UI changes prior to late 2022 (which disables rounded corners on everything and reverts 2019-2022 backgrounds.)
< Feedback on YouTube - Revert UI changes before late-2022 (Non-Rounded Design)
UPDATE: I had to clear cache browser and disabling other scripts to cause conflicting scripts from the Tampermonkey, now It's looking fine without bugs.
Script is working well, just one problem, the "subscribe" button has disappeared. The "subscribed" is nowhere to seen, but has toggle notification button.
Browser version: Chrome 108.0.5359.125