Hi Eliot,
We have a mix of software use - 3DS Max + Corona/Vray, Maya, Twinmotion, Lumion, Blender 3D, UE, Adobe suite, etc. Similar systems except we have 3990x threadripper for CPUs. I think the Xeon's single core speed is low enough to cause a bottleneck with most Max processes being single threaded. Additionally, I would check what type of network speed you have. If you're loading several xref from network on a slow network that could be a headache. We upgraded to gigabit network and that improved read/write speeds.
Even w/ the faster network and workstations. When using max, I break up scene to xref files then when those get referenced in set them to not visible, ignore animation, etc.