Slow Macbook after messing with Terminal app?

My Mac has been working pretty smooth until yesterday. I opened Safari for the first time in a while (because I use Chrome) but it couldn't load any pages. For some reason, the home page is some PDF I opened months ago. I ignored it and used the search bar to look something up on Google, but it couldn't load.

I then looked up this issue with my phone and stumbled upon a video that would supposedly fix the problem. https://youtu.be/c2WU4VJ0sJk

It required pasting a command into Terminal. I was kind of impatient so I decided to type it in, but I made a typo (I placed a space in between "-boolean"). I wasn't sure if this mattered, so I just typed it in again (correctly that time).

However, either it was my typo or that useless "solution" but after pressing enter, I reopened Safari and still got the same issue. Now, the problem also transferred to Chrome. Pages that use to run quickly are now loading incredibly slow. I know it's not my internet connection because every computer action is lagging. None of my apps are responding to clicks or keyboard commands. Launchpad is lagging, Notes now takes ages to startup, etc. (Note: The Chrome search bar is working smoothly as if nothing is wrong, weirdly enough.)

I don't specifically know what I did wrong, but I don't want to try and fix anything without credible help. I feel like file corruption could be the issue I'm dealing with.