As you’re dealing with digital print output, Scribus may be a good option. That’s layout (something of a mix of Illustrator and InDesign), not image editing, but cropping photos is easily done in a variety of FOSS without having to be subjected to the learning curve of GIMP (so long as your RIP can translate RGB into CMYK, which was a solved problem in the aughts). I’ve admittedly only played around with Scribus a bit, but from what I can tell from your use cases, you’re not looking for the bells and whistles like trapping one needs for offset.
GIMP suffers the same problem. If you’re used to CS, anything else is going to be a horrific experience.
I’ve not tried Inkscape. Is it a bit more friendly?