How to make video thumbnail ratio match video

Hi, I used a code that I found to change my squarespace videos from landscape to horizontal. Since I want to add horizontal videos to my site as well and I've used video block ID code to make the ones that I want to be horizontal, horizontal. But the issue now is that the videos that I want to be fully horizontal still appear to be vertical. However, once you click the play button, the video then looks horizontal as it should be.  Anyone know how I can make the videos show up horizontal as well before people click play? Because when its vertical, it's very zoomed into the vertical frame and doesn't look pleasing. I've attached pictures of when its vertical before i press play, and how it turns horizontal after video starts to play.

Hi,

Can you share link to page where you use video? We can check easier