When 3D models don’t show in Blender’s Eevee, start by checking the model’s visibility (eye/monitor icons in the Outliner) and ensuring the viewport is set to Eevee’s Rendered or Material Preview mode.
Next, use Eevee-compatible shaders—avoid Cycles-only nodes like Volume Scatter. Update GPU drivers, as outdated versions often cause display glitches.
If issues persist, isolate the model by hiding other objects or reset Eevee’s render settings to default.