1. site broken after use of speed up plugins ?
2. all speed up plugins deleted but nothing happens - site is still broken ?
3. i am there to help you ! 
4. just go cpanel > file manager > settings > tick : show hidden files

5. edit .htaccess
6. remove all codes and push this codes

BEGIN WordPress

RewriteEngine On
RewriteBase /
RewriteRule ^index.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

END WordPress

7. now click “save changes” – see your site is ok now // nothing broken

** code resource: https://wordpress.org/support/article/htaccess/