I'm using Windows 10 inside a QEMU virtual machine on a Gentoo Linux host system. I need it in order to download e-books with DRM because Adobe Digital Editions only runs on Windows. My QEMU configuration works pretty well. Anyway I would greately prefer not to use any proprietary software.
I try to use free software only, but unfortunately that's not always the case. For example the BIOS of my desktop computer is proprietary. I also don't use a FSF-approved GNU/Linux distribution on my desktop because I prefer Gentoo. But I set ACCEPT_LICENSE="-* @FREE" and I don't have any exceptions in package.license. Unfortunately I still can't enable the bindist USE flag due to some unsolved issues with openssl. I use deblobed linux-libre instead of gentoo-sources. I use LineageOS on my smartphone, which brings a few more non-free software with it. I also routinely run proprietary Javascript code on my browser when visiting most websites.
The positive fact about GOG is that they sell games without DRM. The negative fact about GOG is that they sell proprietary games. This is why I won't support their initiative. Defective by Design by the FSF is a better way to get involved.