Error 0x800f0922 for 2020-01 Cumulative Update for Windows 10 Version 1909 for x64-based Systems (KB4532695)

Your type, attributes, & size on the EFI System partition look fine to me. I wouldn't increase its size. And it's just fine for it to be partition 2. Also, the other partitions look good. The reset seems to have done a good job with that. My Recovery partition is 790 MB compared to your 529 MB, but I think yours must be OK, if that's what the reset did.

(1) What OS Build is at "START, Settings, System, About"...

(2) What do you see at "START, Settings, Update & Security, Windows Update" -- is there a message or any activity going on?

(3) The first thing to try is "START, Settings, Update & Security, Troubleshoot, Windows Update". But say a prayer first that it will actually do anything useful.

(4) Let me see a BCDEDIT & a ReagentC /Info...

(a) Type "CMD" into Search, & click "Run as administrator".

(b) Enter...

BCDEdit

ReagentC  /Info

Then use Ctrl-A & Ctrl-C to copy it, & paste it here. Here's mine...

Microsoft Windows [Version 10.0.18363.720]

(c) 2019 Microsoft Corporation. All rights reserved.

C:\WINDOWS\system32>BCDEdit

Windows Boot Manager

identifier              {bootmgr}

device                  partition=\Device\HarddiskVolume1          << Yours should say HarddiskVolume2

path                    \EFI\Microsoft\Boot\bootmgfw.efi

description          Windows Boot Manager

locale                  en-US

inherit                 {globalsettings}

badmemoryaccess         Yes

default                 {current}

resumeobject       {7f582e76-a2f7-11e9-86db-c6c7375e4034}

displayorder         {current}

toolsdisplayorder    {memdiag}

timeout                30

Windows Boot Loader

identifier              {current}

device                  partition=C:

path                    \WINDOWS\system32\winload.efi

description          Windows 10

locale                  en-US

inherit                 {bootloadersettings}

recoverysequence        {7f582e78-a2f7-11e9-86db-c6c7375e4034}

displaymessageoverride  Recovery

recoveryenabled         Yes

badmemoryaccess      Yes

isolatedcontext           Yes

allowedinmemorysettings 0x15000075

osdevice                  partition=C:

systemroot              \WINDOWS

resumeobject          {7f582e76-a2f7-11e9-86db-c6c7375e4034}

nx                            OptIn

bootmenupolicy     Standard

C:\WINDOWS\system32>ReagentC /Info

Windows Recovery Environment (Windows RE) and system reset configuration

Information:

    Windows RE status:         Enabled

    Windows RE location:       \?\GLOBALROOT\device\harddisk0*partition4*\Recovery\WindowsRE

   Boot Configuration Data (BCD) identifier: 7f582e78-a2f7-11e9-86db-c6c7375e4034

   Recovery image location:

   Recovery image index:      0

   Custom image location:

   Custom image index:        0

REAGENTC.EXE: Operation Successful.

Where mine says Partition 4, I expect yours to say Partition 1.

I set the EFI partition's GUID to c12a7328-f81f-11d2-ba4b-00a0c93ec93b as it should be and retried the Windows installation from ISO. This time it seemed it would continue, so I interrupted it and ran the update I had been trying to install, and it installed without a problem.

I think this might be my issue, as this is what I see:

how would I go about changing the GUID?

You don't seem to have an EFI partition (Type System). Are you using UEFI or Legacy boot? Run msinfo32.exe and look at "BIOS Mode" under "System Summary".

I'm sorry, I'm really dumb, that was the wrong drive. Unfortunately the correct partition (i think) is still showing a different (incorrect?) GUID

I had to dig just a little to actually make sure I was selecting the right drive, and I think I found the system partition on it? For me, disk 5 (the only nvme drive) was the os/boot drive, so:

I'm almost positive this is the correct partition, with an incorrect GUID. 

Is changing the GUID a thing you can even do? My google skills are letting me down on this one

In diskpart select the disk and partition you believe is the EFI partition and

set id=c12a7328-f81f-11d2-ba4b-00a0c93ec93b

You may also want to check the contents of the partition. You can assign a letter to the volume so you can look at it in Explorer:

select volume 8 (assuming your last image is correct)

assign letter=S

then exit diskpart and explore drive S:. You should have a folder called EFI containing two folders, Microsoft and Boot.