While I’ve never encountered a 2-3 hour import, there are a lot of reasons Unreal imports can take so much time, like @ZacD said.
Some of those features that increase import time (static mesh):
- Generate missing collisions (necessary for any gameplay mesh, also very time consuming, per-mesh)
-Remove Degenerates (mesh tool to remove bad triangles. Necessary to keep if not using Nanite, per-tri)
-Build Reversed Index Buffer (from my understanding, only needed for mirroring meshes, can probably turn this off, per-vertex)
-Generate Lightmap UVs (not needed for Lumen lighting, this is only for baking your lighting, per mesh)
-Transform Vertex to Absolute (no reason to disable this, per-vertex)
-Compute Weighted Normals (better for more accurate lighting, per-vertex)
-Convert Scene (should be a quick process, also necessary, per-mesh)
-Material Import Method (if creating materials, needs to internally open the material creation logic, create a material, import the textures, add them to the material, then save that new material. This is done per-material index and can be very slow)
-Reorder Material to Fbx Order (should be really quick, per-material index)
Honestly, the collision generation and material creation are probably what’s taking the most time. 2GB is a pretty big asset for game design, and it sounds like you’re trying to import a lot of assets at once. Keep in mind that Blender is made to open FBX files, whereas Unreal is more of meant to read the FBX files and convert the found components into game assets.