I’ve heard sysprep is super janky w/ modern Windows. Has it been deprecated and replaced with something else yet?
not that i know of, and yes, its really really painful to create a good working sysprepped images. Lately i was looking into building Windows 11 Vagrant images for deployment on libvirt, which, was another kind of fun:
After working around all of that stuff by making packer pass a tpm emulation device (swtpm) to qemu and make it use tianocore uefi bios, after hours, i had an automated install going which failed during sysprep phase, because a OneDrive Appx package was unable to be uninstalled and some error messages followed where no exact reason was to be found. I went on and removed the mentioned package manually and then sysprep finally worked.
All in all it took me about a day to get a working image, and i wont touch that image.. ever.. again (until it breaks, for some reason)