Poster and play/pause buttons will not disappear

I am running W10 1903 in tablet mode.
I realise this is a niche use, but this is my tablet.
Playing a film the streaming is fine (over internal wireless), however even with full screen I cannot get rid of this. Apart from anything else it covers subtitles.
Any ideas much appreciated.
N

Is this using the browser, like Edge, in full screen mode?

Yes (both partial screen and full). You see in W10 tablet mode the only way (at least I have found) of making tiles is using Edge. I have a bunch of links to favorite pages, one of which of course is jellyfin.
I do not have this problem on Android or normal screen modenor using other browsers.
Is this a known issue?
Best,
N

There was a known issue with the web client in certain cases within 10.6.0-10.6.2, but it usually only affected Android. It should have been fixed by 10.6.3.

What version of Edge is it?