Well, I notice that the top text slants upward, and the bottom text slants downward. This is because the left side of the camera was closer to the paper than the right side-- the camera was not held parallel to the paper. When I photograph documents, I use a tripod, and I use a bubble level to ensure that the camera and the document are each held exactly horizontal so that they are parallel.
Lighting is also always an issue. I see shadows across the paper, and that lighting difference makes it more difficult to fix. I sent that page to Photos, and I used the Black & White edit tools to clean it up a bit:

But the iPhone has built-in tools to take care of most of this-- scanning is in the Notes app. You can see this:
How to scan documents on your iPhone or iPad - Apple Support
I was confused in the above about finding the Camera icon. Apparently in iOS 18, the scanning is hidden in the clipboard, so you must choose the paper-clip icon:

And for scanning, you don't choose camera, but you choose Scan Documents. This will straighten the scan and adjust the lighting for you- it turns out very well, I think.
Does this work better for you?