I've used unattend.xml to put C:\Users on a hard drive, leaving the rest on a SSD, so I don't need to think about what files go where. Documentation specifically warns against doing it that way, but I ran Windows 7 and 10 that way for over 12 years with precisely 0 issues with it.
Now I run Linux with / on a hard drive and /usr on SSD.
Normally on Linux you'd put /home on a different drive/partition, which I do mainly for upgrade purposes (I upgrade my root filesystem to a new distro/distro version and then mount my home dir on the fresh install)