Hey James,
I haven’t found exactly what is causing this, but if try an earlier version (I tested 3.0.1 and 3.1.2), you should get a lot better performance.
On my computer (not as good as yours), the file takes more than 30 seconds to load in 3.2 (and 3.3 and 3.4) and if I switch to Cycles, Blender crashes when trying to use Rendered View. (Once I got a ton of “Too many lights” errors before it crashed..)
In 3.0 and 3.1 it takes less less than 6 seconds to load and Cycles Rendered View is also no problem.
This is thus a bug/regression in 3.2 and higher, that should be reported…
I also noticed, that turning off Shadows in the Lights helps with performance, but that’s not really helpful, of course.
