Size difference between steam and dlsite is huge
Yeah, you are right. I have checked and the most discrepant file is "sharedassets3.assets", going from 343MB on DLSite to 7.6MB on Steam. Does this mean that there's cut content? I would say no, but I cannot say for sure.
I checked the files with UABE and it seems that the major difference is the lack of multiple instances of "texture00" and "texture01" (6 assets of 64MB each to be specific), which when dumped show to be random textures of many components of cloth, some toys, and mostly body parts.
Then I checked on the Steam version and they're also there, but they seem to be a pointer to "sharedassets3.assets.resS", meaning that the lower size may just be an optimization of avoiding duplicates. Without checking on that .asset.resS file, which I don't know how, it is difficult to confirm it, but it's the most reasonable from what I see. However, that's just on the largest difference, there might be many others, which I assume are just the official translation and uncensoring.
Something worth of noting is that the size of the .png dump of these assets are 45.7MB in total, meaning that a large optimization in size may be possible at the .asset.resS, but I don't know how or even if it's possible. Maybe it's just UABE performing some type of lossy conversion to .png.