There are different width and height sizes on all phones. When often phones have higher height.

But you want to look at how much pixels you want to use.

Depending on your video creation program, some can show right your video

Here is the list of pixel sizes and viewports that you can learn from:

https://mediag.com/blog/popular-screen-resolutions-designing-for-all/

By my definition I would use 1080 x 1920 pixels for a video. And 1440 x 2280 pixels for more detailed video. This range will become a good video uploaded on perhaps TikTok. And the downscale upscale will be lesser beat than putting a square video out. Especially phones do not render square video properly unless in the middle of the screen.

By using 320 x 568 you can then have videos that are lesser in pixel, but still will look good on most phones. This truly costs lesser for upload through paid internet. But this size will have lesser details. It's good for posters or simple things that need to get out that does not need full quality.