MacOS Safari embedded videos won't expand to full screen

With the most recent Safari update, neither my Apple desktop nor my laptop will let me expand videos embedded in webpages to full screen. Both computers are running OS 15.7.5 and Safari 26.4. The videos play, but won’t expand. When I go to those pages in Chrome, the embedded videos expand to full screen no problem.

Am I missing something here? Is there a setting that controls this? Anyone else having this issue? A search of the web mostly turns up links about videos not playing at all.

Thanks for any help.