FOSS browser addon seamlessly skips embedded video ads on youtube. Interfaces a global SQlite DB (can download a local snapshot) for user votes of what constitutes an ad.
Firefox: https://addons.mozilla.org/en-US/firefox/addon/sponsorblock/
Chrome and Chromiums: https://chrome.google.com/webstore/detail/sponsorblock-for-youtube/ajjollijmimolcncegpgkbilohbhjnhi
Author website: https://sponsor.ajay.app/