Star Trek Armada 3 - Low fps on a decent system

When playing the Star Trek Armada 3 mod my system reports around 15 fps according to AMD Radeon monitoring.

My GPU hovers around 10% utilisation and CPU around 2%.

I was expecting to see either 99% for my GPU or 16.6% for my CPU (1 full core running at 100%).

Can anyone please explain why I have no bottlenecks and yet have only around 15 fps???

Also - I cannot find a proper Star Trek Armada 3 forum !!

Thanks

System specs

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CPU = AMD 5600X (6 core) on X570 m/b

GPU = RX 5600 XT

RAM =16GB DDR4

Monitor 1440p 60Hz