I have the exact same issue with A7VI RAWs and the Microsoft RAW extension.
I figured out it's related to the new Sony lossless compressed RAW format.
A7IV compress or uncompressed RAW are displayed fine, but A7IV lossless compress RAWs are not displayed at all.
The LibRAW blog post from 22. Oct. 2021 says the new Sony losslesss compressed RAW format is now supported.
My guess would be Microsoft RAW extension includes a version that is too old.
I have the exact same issue with A7VI RAWs and the Microsoft RAW extension.
I figured out it's related to the new Sony lossless compressed RAW format.
A7IV compress or uncompressed RAW are displayed fine, but A7IV lossless compress RAWs are not displayed at all.
The LibRAW blog post from 22. Oct. 2021 says the new Sony losslesss compressed RAW format is now supported.
My guess would be Microsoft RAW extension includes a version that is too old.