Have seen the latest updates (KB5010414 & KB5010474) cause my mouse to lose the ability to send keystrokes mapped to the additional buttons. Removing the patches returned the mouse to normal. Error I was seeing when it was occurring in the Windows Application event log is below.
Faulting application name: ArmourySwAgent.exe, version: 2.0.0.8, time stamp: 0xb0659cdc
Faulting module name: clr.dll, version: 4.8.4470.0, time stamp: 0x61b731cd
Exception code: 0xc0000409
Fault offset: 0x0060d4e8
Faulting process id: 0x27dc
Faulting application start time: 0x01d822acf9a6e602
Faulting application path: C:\Program Files (x86)\ASUS\ArmouryDevice\dll\SwAgent\ArmourySwAgent.exe
Faulting module path: C:\Windows\Microsoft.NET\Framework\v4.0.30319\clr.dll
Report Id: 4708ba02-6ac4-4c04-9870-c11564c08f3d
Faulting package full name:
Faulting package-relative application ID: