My modifier keys on my MacBook Pro have stopped working as expected, how can I fix them?

First I'll highlight I've been using this MacBook for about 3 months, it's my first Mac in 7 years, in between I've been using Thinkpads.

This sounds really odd, but the other day I powered up my MacBook pro and my modifier keys had stopped working as expected.

If I'm in Microsoft Office, say Excel, then ctrl-c and ctrl-v work as expected but in other applications commands like cmd-c and cmd-v don't.
The commands for taking a screenshot don't work. The commands for navigating between windows and applications (cmd-tab and cmd-tilde) don't work. In my IDE, none of the commands that involved navigating (optn-cmd-arrow keys) work, copy/paste doesn't work, nothing that involves a modifier and a function keys works.
I am at a complete loss as to why this is the case.
As best I can tell everything looks OK in the configuration, but I haven't used Mac in a while so I'm not sure.

I have not made any changes beyond installing an ANSI keyboard (the MacBook itself has a Nordic layout) but this has been fine for months. How can I troubleshoot/fix this?

Turns out this was a function of my Varmilo M108 keyboard. The Windows key was disabled, which you can do by pressing fn + Windows key. You re-enable it by pressing the same keys again.
I'd bet it was my cat walking across the keyboard that did it when I wasn't in the room. The Windows key doubles as the CMD key on mac.