So I have seen a lot of people having these issues and the any Video you click redirects to a YouTube Help Video saying something like "This video isn't supported on this app". This now has happened to me but I was able workaround it.
I have the solution for you
Go to your Revanced Extended settings and go to miscellaneous. Export your settings in both .txt and as a file just to be sure. (this might still not work to import it into the new app. So if have any special settings maybe take a screenshot or a Video)
Then you can delete all the cache and app data of both YouTube Extended and the Vanced MicroG app and uninstall.
Go to your RVX Manager > Settings > Sources and enter it as it shows on the screenshot I provided. (don't worry, once inotia is back you can just reset this back to default)
Restart the Manager and do the usual.
Go to patch, tap on the recommeded version and download it. Then go back to patch on your RVX Manager and tap on storage on the bottom right and choose the version you just downloaded and patch it.
When done patching and installing after opening the app it'll tell you to that microG is missing and it'll redirect you to the supported GMScore site. Download and install it log back in to your Google account and go back to Import your settings (hopefully it works for you) AAAAND YOU'RE DONE. This worked for me and since I still see so many people looking for a solution I thought I'd share how I made it work again. Just to be clear, this app will still look and work like Revanced Extended but in it's core it now is YouTube Advanced and it works perfectly.