Matt, just to be clear, I only use MME in BIAB. I tried WAS for a few minutes on day 1, didn't like it. I have used my MOTU ASIO with BIAB when I use my keyboard input - work fine. But 99% of my time in BAIB is MME.
Yesterday was a big session of recording work. I am working on my grand OPUS. Lots of BIAB use and Reaper and recording. All went well. I turned off the DAW last night and this morning no joy. Right now massive downloads of Win10 Updates.
Today I am off the day job till next year. So I will let you know (likely more than anyone cares)

how this plays out.
...Win10 updates just told me to "restart".