On Reddit (and as noted by Android font and 9to5google), someone posted an easy way to watch YouTube videos in a web browser without any ads. In the URL of the video you want to view, you just need to add an extra period after the com dot in the YouTube link.
It works as described for me when you paste the URL of the video into the incognito window with the dot added. In addition to removing ads before the video, it also eliminates breaks in the middle of the video for the video. By the time you’ve copied, pasted and changed the URL of the video, I’m not sure how much time you’ll really save waiting for the “skip ad” button to appear, but it really works.
With over 4,000 votes on Reddit, it’s likely that YouTube already knows that people have found out about this flaw. The observation will probably be corrected as soon as possible.
Also, remember that advertising revenue partially helps your favorite creators keep doing what they do. Ad blockers and this trick remove these resources. The “right” way to no longer see ads is to subscribe to YouTube Premium, which you may already know, because the YouTube app relentlessly tells people about it with staggering frequency.