Sluggish 23.5 - CPU at 150-180% While Not Under Load

I'm experiencing performance issues with both 23.4 and 23.5 - I was hoping it was resolved in 23.5. The issue is at idle, meaning in a timeline parked, I'm seeing CPU usage at between 150-180%. I'm editing with 720 proxies off a RAID and if I downgrade back to 23.3 all is well. Anyone else having these issues? Its bad enough that I can hear the fan at full bore if I have Premiere open. Again, no issue with 4k AE projects, or using the same project/footage or higher res footage in 23.3.

I'm on a 2020 5k iMac. Screen shot of activitiy monitor and system attached.

I'd really like to stay in 23.5 since the script editing is proving extremely usefull for rough cutting and stringouts.