Thank you for the supplement advice! I'm definitely going to be setting up my feeders on a better gut loading diet, so I hope that helps with his overall health, too.
Another update: Ramses still hasn't pooped at all unfortunately! I'll probably need to take him in for a vet visit if he doesn't go by next week, but I'm really hoping he goes before then, as I'm hoping he doesn't have anything serious going on. I did try to shower him with his plants this time and he still didn't really seem to like it; he just kept climbing the plants and reaching around like he was looking for more to grab on to. I also added a second small UVB hood to his cage today, as I'm worried now that the first one isn't in a good place for him to get as much UVB exposure (if you can see it in my picture, it's in the back left corner). I put the new one along the open right side to cover more of the cage where he actually sits.
There was another thing that just occurred to me tonight from what you all were telling me earlier on. My other reptiles are set up in the same area (I have a leopard gecko and two blue tongue skinks). The leopard gecko doesn't have any lights to speak of but the skinks both have infrared night lights. The nearest cage is about 2-3 feet away from Ramses' cage. Is it possible the light is bothering him from the skink's lamp, even if it's only in the same area? The second skink is further away (7-9 feet) and blocked partially by the leopard gecko's cage, so I'm not sure if the light from that far away would bother Ramses either.
If my description is unclear I can take a picture of the whole area to show. Basically, my other three cages are lined up in a row, skink - leopard gecko - skink, with Ramses being in front of and to the side of the last skink cage. I can definitely try to move him or cover his cage partially at nights if it could be an issue, but I just wanted to check first before trying to move everything around.