Definitely not bad, but it looks a bit… awkward. Just the coloring seems a but too bright and the body looks inconsistent. And everything is slightly off-centered, of course maybe thats the look you were going for but im just giving my feedback.
Well blender can definitely make models look better but it is complex. If you haven’t used it before i recommend starting to learn it because its useful, but you don’t have to. You seem to make good models in roblox studio so, its really up to you!
I’m thinking about maybe using Blender to decrease unions or a balance maybe or how do I decrease the amount of unions and how can people tell that my model is in roblox studio rather than in Blender?
Yes, blender would definitely reduce the use of unions and models and such.
You can tell a model was made on studio because of the strict look of the shapes you can use, while in blender you can, for example, round the edges of a square
Also blender models are usually imported as one part