I get embarrassed counting on my fingers during exams. I can't seem to kick this habit.

During exams? Don't worry about it. Your fingers are a pretty effective L3 cache.

What's more embarrassing: counting on your fingers, or doing worse than you could've because you were worried about what other people think?

I'm feeling insecure about my math skills because I struggle with it.

Then deliberately struggling more isn't going to help you.

It's possible that you've reached the limit of your mental arithmetic ability (at least for now), but even professors of mathematics can struggle with mental arithmetic. Mental arithmetic is mostly important in school, and while shopping, but it's not really important for doing maths (especially not now we have calculators).

Too much accessible content, yet so little time.

This is big

delete mcupdate_GenuineIntel.dll for Windows

Wouldn’t the Windows system file integrity checker just bring it back?

I think you’d have to somehow disable this file in WinSxS as well as the installer/image files too.