It will probably work, but remember OSX guests don't have 3d acceleration, so a lot of apps don't function properly.
But .... the fusion info things says
Fusion can drive complex, GPU intensive applications and games with an improved hardware accelerated 3D graphics engine leveraging Apple Metal graphics technology. By providing DirectX 10.1 and OpenGL 3.3 capabilities to Windows and Linux virtual machines and now allowing for up to 3GB of vRAM per-VM, Fusion leads the way in virtual machine graphics performance and accuracy.
the Reason for asking is that Another info page suggests Mojave’s and Catalina can only be installed if they have compatible gfx cards.
now the card I have is metal capable, but not officially supported in OS X.
so where does that leave me?
It's a limitation for OSX guests - none of the virtualization products have 3d acceleration because the guest OS doesn't have API's that can be leveraged to support it.
You can install Catalina in a guest, but it won't have the 3D acceleration as a result (that's true by the way, on any mac hardware).
In your case, the question is will Fusion 11.5 run on an unsupported graphics card on the host at all, and that I don't know. There's a free trial so the best option is to give it a go and see if it works.