I usually just upload cropped photos from my phone. No editing except maybe a vignette filter to the edges. If your phone is one from the last few years they’re generally not terrible.
Editing photos after would be best on a monitor where it has been properly calibrated for color. That’s the easiest way to make sure most colors match across screens.
I haven’t checked to see what the compression is through MorphMarket’s photo uploads is like. I also haven’t messed around with capcut to see how the editing tools are.