How to install Mac OS 14.5 Mojave onto VMware Fusion 11.1.0?

Have you tried going to  Add > New > Install OS X from the recovery partition in VMWare Fusion?

http://partnerweb.vmware.com/GOSIG/MacOS_10_12.html

Do you have a recovery partition on your Mac Pro? You can test this out by holding COMMAND-R on power on. If that takes you into Recovery Mode (and didn't have to download it over the Internet) then VMWare should be able to install from that before having to resort to more roundabout methods to get the actual installer.

You can get the installer from these links:

https://krypted.com/mac-os-x/download-older-versions-of-macos-and-mac-os-x/

FWIW, although you can create a Mojave guest in VMWare Fusion, it's very slow even with 8GB and 4 cores. I would suggest once it's available you install 10.15 in a partition or external drive.