When tested on an iPhone, a video doesnt play inline in browser. the videos are embedded using regular video tag.
<video webkit-playsinline=”” playsinline=”” id=”my-video_html5_api” class=”vjs-tech” preload=”auto” src=”https:/path/of/the/video.mp4″></video>
as you may see, webkit-playsinline and playsinline attributes are used and still it doesnt work. The video plays fullscreen on iPhone once clicked (it works correctly on iPad though)
I suspect this might do the trick, but not sure as i dont know the internals.
https://developer.apple.com/documentation/webkit/wkwebviewconfiguration/1614793-allowsinlinemediaplayback