There are extensions that can swap the thumbnails with a frame from the video. It's not as good as a handpicked frame, but it's a lot better overall compared to

There are extensions that can swap the thumbnails with a frame from the video. It's not as good as a handpicked frame, but it's a lot better overall compared to the garbage youtubers are making now. The one I use on chrome is called "clickbait remover for youtube"