I dont know if this helps.
I logged onto the server a different account (still domain admin) and it applied the updates.
However, now it is 'checking for updates', I can see WER reports in the application log.
Most of them are:
Fault bucket , type 0
Event Name: WindowsWcpOtherFailure3
Response: Not available
Cab Id: 0
Problem signature:
P1: 10.0.14393.3622:3
P2: wcp\componentstore\versionedindex.cpp
P3: ComponentStore::CRawStoreLayout:
opulateComponentFamiliesKey
P4: 1021
P5: c015001a
P6: 0x1108dbba
P7:
P8:
P9:
P10:
Attached files:
These files may be available here:
C:\ProgramData\Microsoft\Windows\WER\ReportQueue\Critical_10.0.14393.3622__903b9d468de170b55adb41fbf449856df2bb1daa_00000000_2a9e8448
Analysis symbol:
Rechecking for solution: 0
Report ID: 1b2d8c76-843d-11ea-a387-6a9ea8450ed2
Report Status: 4
Hashed bucket:
or
Fault bucket , type 0
Event Name: WindowsWcpOtherFailure3
Response: Not available
Cab Id: 0
Problem signature:
P1: 10.0.14393.3622:3
P2: wcp\identity\id_authority_helpers.cpp
P3: Windows::Identity::Rtl::Implementation::CRtlIdentityAuthority:
arseAttributeList
P4: 732
P5: c000000d
P6: 0x2b034e74
P7:
P8:
P9:
P10:
Attached files:
\\?\C:\Windows\Logs\CBS\CBS.log
\\?\C:\Windows\Logs\CBS\CbsPersist_20200422011503.log
\\?\C:\Windows\Logs\CBS\CbsPersist_20191105101844.log
\\?\C:\Windows\servicing\Sessions\Sessions.xml
\\?\C:\Windows\WinSxs\poqexec.log
\\?\C:\Windows\Logs\Cbs\FilterList.log
These files may be available here:
Analysis symbol:
Rechecking for solution: 0
Report ID: 0061590a-843d-11ea-a387-6a9ea8450ed2
Report Status: 262144
Hashed bucket:
The CBS log file is attached.