It sounds like I have the same problem (Google Pixel 5). I think it started happening after I did an update to the camera app but I don't know if there's a relationship between the ebay app and the phone's camera functionality. If I use the ebay app and take a photo (and don't change any settings), what is shown on the screen is not what appears when the photo is added to the listing. The resulting photo in the listing is cropped.
The workaround I found is to begin to take a photo but before pressing the shutter, I have to click that square icon with arrows on the top of the screen. It looks like it represents "full screen" or something like that. Once I do that, what I see on the screen is what I get in the photos for that listing. I have to click that icon for each new listing. If I don't, every photo comes out cropped. Super annoying.
