Banner videos not playing in newer iPhones and Samsung?

I have banner videos on my index pages and they look great and load with minimal delay on computer, laptops and phones older than iphone 10s.  HOWEVER, iPhone 10XR and 11 and newest samsung doesn't play the videos at all (defaults to mobile fallback) AND even refuses to stack page images and text the way all the other older iphones do.  Anyone else experience this too?  Any hacks or fixes??

Just finished with customer support. Same issue. Even the mobile fallback image refuses to display. Just a blank grey space where the banner video/image should be. Works fine on iPhone 7, but not the iPhone X. CS said that it's an open issue with no resolution at the moment, so they wouldn't even log a case for me.