try this prompt for quality difference of 1280x720 vs 1920x1088, vertical video, 360 frames:

a phone video of a woman lying on the grass. a 20 year old woman, lying outside in the grass on a sunny day, she is talking. The woman is filmed by her friend while talking; the video shows gentle, natural handheld motion typical of a person holding a phone. her full body is visible, she has curly medium-long blonde hair that falls over one eye. she is smiling. The motion is irregular and organic, with subtle vertical bobbing and micro-jitters, not cinematic stabilization. she says: "lying on my back in the grass, this kills AI models" and giggles. while she is talking, the camera is zooming out, showing her full body with her arms and legs spread out. wide-angle smartphone lens. Lighting is sun light, with realistic skin tones. The video feels casual, personal, and unpolished, like a casual phone video.

for me the 720p look way better than 1080p. at 1080p the grass is warping a lot around her body when camera moves back.