They may have actually had projector issues because I didn't have any problems seeing anything. It is not a brightly lit film for sure but the cinematography worked for me.
I personally loved the more washed out, heavy use of shadow cinematography that mimics the OT. But, they aren't wrong about the cinematography in Solo. The movie gets really dark at certain points that you literally can't make out what's going on. I still liked the way the movie looked, but that can't be ignored.