Lovely system. And I'm sure that it sounds just great rightside-up or upside-down! Before I would invest in a lot of new equipment I'd try to get the very best from what you already have, specifically I'd try some simple room treatment if possible. This could improve your imaging, image specificity and hopefully less phase distortions that tend to plague smaller listening rooms. All of your equipment is high quality and when give the opportunity to shine should produce very natural and convincing sound.
Another inexpensive upgrade would be your phono cartridge. Several hundred dollars in this area can improve or certainly change the sonic signature of your system. Nothing wrong with the Oyster but other cartridges can provide greater detail and clarity for not much more money.
All in all don't mess with cables at this point. You have respectable levels already and although cables can have an impact and I believe that they truly do, source components like phono cartridges usually have a more obvious if not profound impact on systems sound especially since it appears that you do not have a digital front end in addition to you analog front end.
I like it and please keep us abreast of your changes!
Thanks! It’s funny... When I look at the pictures on my phone, they’re right side up. But when I look at them on my laptop, they’re upside down. I’ve seen other systems on here with the same problem. I uploaded the pics using my phone. I wonder if that has anything to do with it.