A fresh install refers to formatting / or root partition and doing a fresh install on that. It is OK to reuse a /home partition IF it is similar. So if the /home was for a Plasma6 system and you are installing Plasma6 that is OK. Not a good idea to use a /home from some other Linux distro for OMLx systems, that can lead to problems.
The iso you are talking about was rejected in testing. When you are using stuff that is in testing you should expect problems that is why it is still in testing. Edit: Also simply upgrading the #3876 iso with sudo dnf --refresh dsync should bring it up to date with the released isos.
Download one of the published to the public isos here or at SourceForge here.
Edit: If someone specifies any system partitions beyond / such as /boot/ or /usr of course those should be reformatted. One exception is /boot/efi you can use one
/boot/efi for multiple systems, it is designed to be used that way.