I created this UGC item to upload, and it looks great in studio, but putting it on a character lowers the quality.
I have tried using a MeshPart, which fixes the texture but can’t be used to upload. I have also tried using a Texture item inside the handle, but that can’t be uploaded as UGC either.
The last thing I have tried is changing the resolution of the texture. The texture for the models in the screenshot are 512x512, and going any lower or higher makes the texture quality worse.
Unfortunately the best way to optimise against this is to optimise your UV-map to work well with smaller texture sizes. It’s worth noting that this won’t affect R15 characters after upload since Roblox converts accessories to MeshParts when loaded on an R15 character.
I tested this by uploading the UGC and you are right, it does look normal in R15, but in R6 was worse than the models in the screenshots. Would be great if Roblox updated R6 accessories to load as MeshParts.