I tried to add 32-bit floating point support, but the only way I could get that to work was with exclusive mode. The shared device never offered an option to configure it to floating point, which defeats the purpose in this case.
I wonder if that means devices which list 32-bit support are only using integer mode? (and even so, perhaps that would still be better than 24-bit?)
I tried to test it, but both 32-bit integer and 32-bit floating point worked with WASAPI non-exclusive mode to those devices.
I'm not sure if there's anything which will tell me what their "32-bit" option is.
I also noticed that since the Fall Creators Update, the JRiver WDM driver has the option to change the speaker setup via the context menu of the system volume control.
All my other system devices only give me the option to change spatial sound options there, not the speaker setup.