These are two of the issues caused by lack of 3D graphics support for older macOS guests. This is a limitation of macOS itself, not specific to VMware Fusion (it also affects Parallels Desktop and VirtualBox). Up to macOS Catalina (10.15), macOS running as a guest has no hooks which would allow VM software to virtualise the 3D graphics capabilities of the real GPU.

The slow performance of LaunchPad and DashBoard are due to them working around the lack of 3D graphics hardware by using a slower CPU-based implementation of 3D (probably OpenGL). The black display in Maps is because Maps uses an API which requires 3D graphics hardware and has no software workaround, so it can't display anything. (A similar problem occurs in the iWork '09 applications, which show all white documents because they require QuickDraw 3D to render the content of the document window.)

If you are running macOS Big Sur as both host and guest, and have new enough VM software, macOS Big Sur has a new feature to paravirtualise the 3D graphics hardware, allowing it to be used in a macOS guest. I haven't tried this yet but based on comments I've seen here, it sounds like it is best classified as experimental and is not ready for serious use.

Assuming this improves, it means that Big Sur or future macOS versions running as guests (on new enough hosts) will be able to use 3D graphics, but this won't help to run older Mac applications which require 3D graphics and an older macOS version (e.g. the iWork '09 applications which are 32-bit and therefore require the guest to be macOS Mojave or earlier).