Botched up Windows Update has broken my Windows 10 (June 2021)

Question

So, the first problems started due to a botched up update on my windows machine(the computer was restarted..it restarted, but somehow the updates didn't occur)

Now, 2 weeks since that, here is my computer now(p.s. my computer behaves irregularly like this, not always)-

1. Windows Modules Installer worker constantly eats up my CPU, on gd days 25% and sometimes it creates 2 sister processes, each eating 25% :((
2. My pc has gone from being smooth to being choppy...Example- If i run a RAM intensive app like MS Teams(shudder) or any web browser like chrome or edge, my pc starts lagging.. And if I naively click multiple times...well, my comp freezes and taskbar goes black and MS Teams audio keeps on running, which puts me in a cycle of restart pc -> open app -> if hang -> restart pc
3. I ran DISM and sfc tests(even Win memory diagnostics)..DISM reported no problems..sfc ...well ran at the start and, till now, refuses to pass the verification stage.. Memory Diagnostics returned clean too..
4. Windows Update Troubleshooter(being the precise shooter it is (no pun.. it sometimes works)) failed to troubleshoot my problems
5. Running the trio bootrec commands went as follows- fixmbr and fixboot worked...rebuildbcd, didn't
6. Antivirus ran pretty clean, reporting no virus or malware
7. New issue my C drive has started refusing simple read/write commands like if I uninstall a program and try to delete it's files...it gets stuck in calculating stage and doesn't delete the files

Enough of problems then...so, I am stuck pretty much and am guessing my C drive is pretty much near ded..

So, can someone please recommend some commands or tools to repair the C drive (Data is backed up, but this is my family pc and I dare not reset it)

Thanks in advance

Hardware-

1. Win 10 Pro 21H1 version
2. Gigabyte motherboard
3. 4Gb RAM
4. 125 Gb SSD(containing the windows) and 500Gb WD hard drive

EDIT1- Forgot to include I ran a SMART test on my pc...My SSD has 87% health and....instead, my HDD is failing ;))

My SSD's SMART test

Funnily my HDD's SMART test ;))

EDIT2- New problem identified: Now apparently I can't delete a single file stored on any subpart of my SSD(C:)..Example- If I download something, I cant delete it..But I can cut-paste it to my HDD and do what I please with it...... Please help folks

EDIT3(6/7/21)-I scanned my pc for malware with a different software..and guess what!!I had 17 malwares hiding snuggly in my registry :((

EDIT3.1-I made a new question regarding a potential answer to my problem's source... Continue here

Answer 1

[I'm aware this is not what he asked - considering the issue it still may be the best approach.]

This may not be what you're hoping to hear, but as I'm dealing daily with those issues, the best advice you can and will get is the following:

• Backup your data
• Make sure your drives are still healthy (run disk checks, etc. from a bootable USB [Linux Live System] - there are tons of guides available - currently on mobile though)
• Swap your hard drives if needed
• Follow up with a clean install of Windows

Why is this the best solution (From experience as a SysEngineer with 10k Windows nodes in my previous/current job):

The chances of getting your installation fully working again without tripping over countless other issues is very, very slim. Those issues may occur directly or after weeks/months and may keep piling up to the point of no return regardless of your measures. Additionally you'll benefit from a fresh and clean environment and you'll get rid of tons of no longer needed files/folders. Windows Updates - especially feature updates as f.e. 21H2 are known to cause issues of that scale and nature.

In the end it's up to you if you wanna continue troubleshooting, but if you don't wanna invest countless hours holding on to a glimpse of hope, I strongly suggest the method mentioned. ;)