Hi @JimBruce
You are able to turn off the floating feature for each video within the video placeholder settings.
Go to your Video dashboard > Video Placeholders > edit the placeholder (select the pencil) > and there will be a ticket list of settings when a URL has been added to the placeholder, there you can turn off Floating by unticking the box.
This video floating feature is still fairly new compared to the anchor ads you are referring to, and every site earns differently. What you could do it test floating video on a few pages and compare the reported earnings after a while to pages which have the floating video off. I would suggest giving the system time to learn the setup before