How do I widen the content width on the screen?

I want it applied to every post. I'm not seeing a difference when I preview updating the container to 2,000.

I just checked your site again and its actually significantly wider now as shown here:
https://share.getcloudapp.com/wbu9XjDD

You can see on the video that the post contents have moved closer to the edge of the viewport.

Are you not seeing the same thing on your end? If so, you may have to clear browser cache.

Maybe it's just not showing that way on mobile? I don't have a desktop or tablet to view those.

I'm not sure what you mean. Here's how your page looks like on mobile.
https://share.getcloudapp.com/X6u9RqPL

If the space on the sides of the content for mobile is what you're pertaining to, that's a completely different setting.

That space on mobile is from the Content Padding setting in Appearance > Customize > Layout > Container as shown here: https://share.getcloudapp.com/v1uNO5dD

I think I've got it figured out. Thanks for all the help with this!

Nice one! Glad you got it figured out. No problem. :D