I'm also seeing the CPU issue when the GUI for an active instance is displayed. I had this issue on 6 as well and opened a ticket (Case 297541) about the problem.
My steps to reliabliy recreate the issue are below. It makes sense there would be additional CPU usage for drawing the meter but from my observation using the test outline below jumping from ~20% to ~100% showing a single meter seems like something else could be going on as well.
Launch VE Pro Server
1. Create two Instances
2. Load Instrument in the first instance (I picked the VSL Concert D)
Launch new project in DAW (I'm using Cubase 10.0.20)
1. Create a new VEPro Instrument
2. Create a simple midi part (I wrote in a couple block chords for a 4 bar loop)
3. Start Playback
Launch Activity Monitor and find the Vienna Ensemble Pro process
1. Observe high cpu usage
2. Go to VE Pro and change the selected instance to the 2nd instance (the one that has no activity)
3. Go back to Activity monitor and. observe the cpu usage of VE Pro