I did an experimental reinstall of Windows 7 on a spare drive to try to see just where the ClientPatcher broke/froze. I wasn’t successful as I spent a lot of time and effort trying to get it to an actually functional state and lost sight of the step-by-step testing procedure. At the end, the system was functional but the patcher process still froze; but I at least know what was in the system by that point:
Windows kb976932 (Service Pack 1)
kb2533552
KB3020369 critical update?
kb3125574 rollup update
KB3138612
KB3145739
KB3172605
kb4474419
kb4490628
kb4530734 monthly rollup
kb4531786 - All these were marked as important updates.
windowsupdateagent-7.6-x64
wufuc_v1.0.1.201-x64
DirectX package
Logitech unifying250 and SetPoint6.70.55_64
Radeon-Software-Adrenalin-2020-22.6.1
MSI board drivers: chipset, USB, LAN, audio