I know nothing about the technology but the alternative is creating a 3d model of my living room which is also outside my skill-set.
Yes, its what the autonomous car people are doing.
However you might want to do photogrammetry first (https://github.com/alicevision/meshroom opensource) as that produces a mesh which you can use to detect collisions easier. The downside is that transparent objects render really badly. but it is a lot faster to render
For training you can do a hybrid geometry plus splats workflow. Have geometry that you can constantly raycast against and have as an input to your vision training or to get accurate depth buffers.
The workflow for splats and photogrammetry are very similar.