Blender to Substance Painter issue

I’ve been learning Blender by myself for a while and I was just able to get a hold of Substance Painter.

Now my question is related to workflow a UV’s. My model is a static model so it’ll not be used in game or animations. It’s a high density sword (Close to 4 million vertices) and I’ve been having problems when trying to paint it in Substance.

Now at first I thought it was bad topology. Since its a high dense mesh then maybe things are going wrong. But after some digging I discovered that its probably due to UV’s being too small so they can’t hold enough information for high quality painting which brings my question.

Is it NECESSARY to retopo your object to paint it properly in Substance? I tried cutting small pieces of the mesh such as just the grip of the sword and Unwrapping it alone and the paint does work a lot better.

I thought then well then maybe I can cut the sword on pieces, paint each section by itself (Such as just the grip then just the blade so on) and then just merge it all together in the end right? But wouldn’t that screw the textures again later on due to the UV’s being on the same map?

So do I have to retopo a high poly count mesh? What is the workflow for this kind of thing?

I don’t think anyone around here wants to help with Substance Painter issues, even though Blender supports SP.

I’ve posted similar q’s and get absolutely no response.

Shameful.