You were correct that my DAW (Reaper) is able to bypass the windows audio subsystem entirely and use the interface directly. I just wanted to clarify in case anyone has a similar issue how I fixed it. By default, Reaper, and perhaps others, use sound system that works off the windows one, like this:
The fix is to simply switch to the ASIO system, like this:
Why on earth it wouldn't DEFAULT to this is a mystery to me. Anyway, thanks for the help! I wouldn't have figured it out otherwise!