I have saved several drawings as DWG without crashing, but they didn't have Architectural features, so I created one.
I had no problems either Saving As DWG, or Open Dwg. Both files are included here.
Only a few of the Architectural features were used. I did not add a Slab, Roof Slab or Roof, let alone the second floor indicated by the stairs, so you should upload your own TCW file for us to experiment if you want to track down the cause of the problem.
TC Pro Platinum 2020, 2019, 2018, 2017, 2016 & 2015 (all with LightWorks & RedSDK) & V21
System: i7-5820K @ 3.30GHz, ASRock X99 Extreme4, 16GB DDR4-2133 RAM, Gigabyte GTX 970, Samsung NVMe SSD 950 (256GB), Windows 7 Pro (64-bit) SP1