If I were doing this with the intention of having a scalable and repeatable solution, I would:
Place an invisible group/button over the entire video thumbnail region, both of which would be encapsulated within a parent group that has a Type of ‘Video’ (or whatever your data type is) — Save this whole block as a reusable element so that your workflows can be repurposed across different areas of your app. This can be done without going full-reusable, but it’s a good feature to learn and have in your toolbelt.
Then, in a workflow for the invisible group set an On click event -> Navigate to page with video embedded (in the video options select ‘play this video automatically on load’ checkbox) -> Send data to group after page load and select the Video thing from the parent group of your video+invisible layer combo.
This would prevent the video from being played while allowing people to still see the thumbnail. I have this sort of thing hooked up on our app except I have a popup appear with the video which autoplays.