Won't fusion 12 run on Mojave 10.14.6?
No it does not.
You need at least macOS Catalina in order to run Fusion 12.
See also:https://docs.vmware.com/en/VMware-Fusion/12.1.1/rn/VMware-Fusion-1211-Release-Notes.html
(system requirements are the same on 12.0)
--Wil