Background video not playing on recently published sites

I’m unsure why Webflow background videos don’t work either when there are a number of examples of them working and I’ve also seen many more examples on other sites. I cloned the site above and tested to see if this worked in one of my sites and had issues with it playing.

I’ve spent a little while trying different combinations and came across some of these solutions. Embedded video not playing/showing on mobile devices - #12 by JackHeathcote
Video Background not playing - #6 by choreus (I’m not experienced with coding so found this hard to implement)

I also saw this Webflow example -
With the cloned Mimim Hero site (from above) I added a HTML Embed, which seemed to work - Webflow - BG Vid Test

This was my rough attempt to get the video to work with a HTML Embed and as you can see I couldn’t quite work out how to get the video to go quite fullscreen when the browser is resized. Not sure what was missing from the HTML code to make it fullscreen (or if any of the other options are better for fullscreen BG videos) but any help would be greatly appreciated.
If anyone has a simpler solution please let me know. TY!