Brand new Mac for Twinmotion and it crashed already - help please.

Hi - I recently bought a new Mac with upgraded hardware specifically to handle Twinmotion. After only 3 days of use I got a complete shutdown and this message that came up saying my computer was out of memory. It says Twinmotion was using 45GB of memory? Did I drop in one too many objects with a high file size and maybe that did it or is 45GB normal? I also had changed the main ground plane set to be water so not sure if that did it? The house itself is only 8000sf. I thought 16GB was sufficient for single-family residential projects. Does anyone have any insight on this and if 16GB is enough memory? The computer is literally brand new, thanks much.

Computer Specs are:

iMac (Retina 5K, 27-inch, 2020)

Processor: 3.6 GHz 10-Core Intel Core i9

Memory: 16 GB 2667 MHz DDR4

Graphics: AMD Radeon Pro 5500 XT 8 GB

Storage: 500GB