Texture painting a model designed for 3D printing

Hey all

I mostly use blender for designing models for 3D printing. I'm interested in learning to paint models in blender because I think it would be cool in future to be able to do nice colored renders of my models.

I wanted to practice on this model from Artisan Guild, but I'm having trouble even getting started due to the number of vertices in the model. Models for 3D printing don't tend to care about good topology or vertex count, so smart uv project doesn't do a great job (one brush stroke puts little flecks of color all over the model even when "unwrapped").

Is there a quick workflow for importing models designed for 3d printing in a way that makes painting them possible?

https://preview.redd.it/wghus32rbqih1.png?width=979&format=png&auto=webp&s=0942bd424be91940f6ec6bbbf0f7016f23406be3