Nginx URL rewrite to directory name shows no changes

I've been trying to rewrite some Nginx location urls but can't get it to work.

For the directory structure /dir1/dir2/index.html, where I will have several different dir2 directories and dir1 is just for organizational purposes, I want to rename the urls to:

mysite.com/dir2

This is my best guess.

location ~ /dir1.*$ {
    rewrite ^/dir1/(.*)/.*$ mysite.com/$1 break;
}

I've tried several variations on this, and I can't get anything to change at all. Clicking on the link just results in:

mysite.com/dir1/dir2/index.html

Here is the full config:

server {

      root /var/www/website;
      index index.html;

      server_name mysite.com www.mysite.com;

      location / {
              try_files $uri $uri/ =404;
      }

      location ~ ^/dir1.*$ {
              rewrite ^/dir1/(.*)/.*$ mysite.com/$1 break;
      }

      listen [::]:443 ssl ipv6only=on;
      listen 443 ssl;
      ssl_certificate /etc/letsencrypt/live/mysite.com/fullchain.pem;
      ssl_certificate_key /etc/letsencrypt/live/mysite.com/privkey.pem; 
      include /etc/letsencrypt/options-ssl-nginx.conf;
      ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
  }

  server {
      if ($host = www.mysite.com) {
          return 301 https://$host$request_uri;
      }
     if ($host = mysite.com) {
          return 301 https://$host$request_uri;
      }

      listen 80;
      listen [::]:80;

      server_name mysite.com www.mysite.com;
      return 404;
  }

I check and restart Nginx every time. Maybe the Certbot config is interfering. What am I doing wrong?