This is quite comfortable PC to use as WORKSTATION for unreal.
Why unreal EDITOR needs so much? Because when you develop you are running quite heavy game like application, tyhat is editor). Then you open content browser on another display with 50 HDRI 8k textures (each about 200mb), then you create one master material from some of those textures, then you make two (or more instanced materials each with different HDRI tex), then you run your game in standalone mode to see if everything runs fine.
So you are running 5 times more textures than some AAAA games do now (like DOA veliwhatever). And this all needs RAM, VRAM and cpu, oh and fast SSD.
ps.
what i would change about this setup is separating some of ssds into UNREAL only drive. Like those two 2tb drives: one for unreal, second for unreal cache (marketplace, projects backups etc.)