gog-games didn’t “shut down” in the past?

Thanks for the correction.

It shouldn’t be a difference, what Ublock and Brave and network based blockers such Pihole do is they have a list of domains that are not allowed to load on your system.

If they find that www(dot)adexample(dot)com is trying to load in your browser, they simply block it and the video continue.

Maybe the only different is the privacy itself that offer something like Libretube vs something like YouTube + Ublock. While using Libretube, you are only loading what is neccesary, you are not giving Google more information that you shouldn’t, and while you using YouTube in Firefox for example you are loading all the cookies, trackers and that stuff, even in private browser with maximum privacy settings and adblocker.