I'm not sure what you mean by enabling 3rd party apps\services because I can turn on all apps & services, and Fences' Peak will still work on the new admin account OR I can turn off all apps & services and Peak will still not work on my old admin account.
Note, when I disable all (non-Microsoft) services there are a few that System Config will not let me disable. I can't turn off: 3 of the AntiVirus Avast ("aswbIDAgent", "Avast Antivirus", and "AvastWscReporter"), and one other service: "Malwarebytes Service"). Then when I disable all Startups in the Task Manager I can't disable "Avast AvLaunch component". I tried disabling Avast for 1 hour after the reboot but it did not make a difference. Peak still always works on the new Admin account but not on the old one.
So it seems that enabling or disabling all apps and services does not affect either the old or new admin account. Peak always works in the new admin account but not in the old one.
I also tried running in Windows Safe Mode but I could not get Fences to run. It said it was not installed.