I have experimented with process lasso and found something that seems to work. went to I/O priorities and matched DCS with low priority. Seems to force DCS to not assign I/O E-cores. Relaunched DCS fter a reboot a couple times and I have not experienced the spikes and the log show no I/O cores assigned. Not sure if this is affecting anything else though as I do not really know what I'm doing here 🙂 Anyway, worth a try!
Brainfreeze's post in VR random Frametime spikes was marked as the answer