this guide will help you to remove all liked videos from your youtube account
1- go to this link > https://www.youtube.com/playlist?list=LL
2- enable developer console (by pressing F12)
3- paste everything in paste.txt to your browser console (https://github.com/willien3lson/clear-all-liked-videos-from-youtube-account/blob/main/paste.txt)
4- wait until it removes all videos, you need to refresh page after every 100 videos. if you want to clear all faster, you can change the speed in the code but your browser may crash.