A 1x1 video would be a better fit for Facebook ads since it'd be suitable for many devices: mobile, computer, pad, etc.
The vertical video ad is only popular with mobile platforms & social apps such as Instagram & Tiktok.
Hope this helps.
Video ads are the better ways to advertise your product on social media especially when it comes to appraisal but sometimes due to the unavailability of the desired device. It may be a lack for getting more sales.
I would like to suggest that try to use vertical videos on the platform which have better UI for the mobile phone like Facebook, Instagram and for the platforms like youtube, try using landscape video.
And if you are still confused about the videos then try to use carousel ads on the different platforms because it is more attractive than other types of Ads.