Create a same flex item for both photo and video

Sun
How can I create a flex item which will allow me to set either photos or videos (depending on what I choose to upload in the collection entry) ? 
Thank you!

Filling a content box with video

Sun
Is it possible for a video to fill an entire content box ? (As the "Cover" option for images)
Thank you !
Sun
Hello 👋

I want to create a flex layout in which when we are scrolling, each item take the exact same place as the previous one by fading up (opacity goes from 0 to 1, unlike the sliding effect of the arkitektur template homepage).

Is it possible to do it ? 

Thank you in advance for your support!
Sun
Hello bondlayer community 👋
Is it possible to create a text reveal like the gif below ?
I would like the animation to begin right away without having to scroll.
Thank you!