There is no direct way in Cubase to see that. The latency number don’t have any direct correlation to CPU usage.
The best you can do is disable (alt+click) the insert step by step and see if that makes a difference on the performance meter.
Usually, it is not just one plugin though but often long plugin chains on a track.
Thanks - thought perhaps there was some setting I was missing.
In Reaper and StudioOne, you can see the CPU load of each VST, which would really be helpful. I wish Steinberg would work on more of these cire workflow features rather than some new instrument or other wacky, edge case usable thing,