Hangs when Nvidia performance mode enabled

[demangler]

Works fine if Nvidia on-demand mode, hangs at what seems to be X starting up if Nvidia performance mode.

System:
Linux version 5.4.0-121-generic (buildd@lcy02-amd64-013) (gcc version 9.4.0 (Ubuntu 9.4.0-1ubuntu1~20.04.1)) #137-Ubuntu SMP Wed Jun 15 13:33:07 UTC 2022

Driver Version: 515.48.07
X-11:
version number: 11.0
X.Org version: 1.20.13

xfmw4

Akitio node with RTX2060
Dell 7577 with GTX1060

I used egpu-switcher for years with this setup ok with an older nvidia driver (470). Recently re-installed mint linux and defaulted to to later driver and now have this issue.

Makes no difference if I load nvidia modules at boot or not.

Almost definitely a driver issue and not a bug with egpu-switcher, however posting here in case there is a workaround and/or help troubleshooting.
I will totally get it if you want to close/delete this - as it is not a bug. Just didn't know where it might be more helpful. :)