Hi there, this is about 3-4 days project (move faster and break things right?)) )
Modular level still more flexible and scalable than this project
Final scene in plans <10k
Scene runs in web gl pretty smooth (1 collider on floor, just dont run througth walls now 
)
In game screenshot
Looks like horror game scene)
https://www.gamebucket.io/game/5acbc02f-9705-4143-96b6-3345b0e73f9d
PS its not my idea - just another course on udemy, another approach, different workflows etc. (special for texturing, UV organize etc)
greatly helped to structure knowledge on the topic