I too encountered this problem starting last week with all of my embedded youtube videos in Powerpoint that I embedded using the youtube embedded code (or URL).
Sadly, there is only one workaround that I've discovered--if you have a youtube premium account (which prevents ads), you need to use office.com. Then you'll need to upload the powerpoint files you need, and play them through the powerpoint in Microsoft's online 365 version. It's tedious and what's worse, if you don't have an end point on your video, you'll need to play the video clip all the way to the end if you want to advance to the next slide.
OR--you can download every video clip you need, but that will place you in legal jeopardy with youtube.
Google needs to squeeze every dime they can from their users, since clearly they're having a tough time making a profit.