I'm new to editing videos in general but I recorded a few things on my phone and then put them onto DaVinci Resolve as a test then uploaded it to youtube but the video is always very small on youtube and i don't know why? Is it because i recorded it on my iphone?
Youtube re-encodes different resolution video files from your upload. Starting from the small ones. Could it be, that it has just not processed the bigger resolutions yet?
Are you sure that the file you exported from Resolve was in the intended resolution? I don't see how the source (iphone) would affect this.