>>297942807
1. Use whatever workflow works best for you. I usually build assets in separate blend files, export to fbx and import into unity to do the composition.
2. If you're trying to do quest worlds, probably <500k tris. For PC, there's really no limit, maybe 20 milion tris practically. GPUs can push 10s of millions of tris at 144fps at this point. Better to build at full resolution first, then decimate/LoD as necessary. don't prematurely optimize. 50k tris is really tiny. most people's avatars have more tris than that, in (possible multiple) skinned meshes.