I can say I rarely handle websites that use shared hosting. And this bad effect I have forgotten what the optimization can do, although the name shared hosting is all limited.
One of them we can use the code in the file. Htaccess to set some treat Apache or LiteSpeed web server on certain content types, and I will write per part of its specific function. Here is the htaccess code I normally use by default of any type of site and its CMS. So its generic.

Expiration settings (expired) of static files
<IfModule mod_expires.c>
ExpiresActive on
ExpiresByType text/css "access plus 14 days"
ExpiresByType text/xml "access plus 0 seconds"
ExpiresByType text/javascript "access plus 14 days"
ExpiresByType application/x-javascript "access plus 14 days"
ExpiresByType image/ico "access plus 14 days"
ExpiresByType image/jpg "access plus 14 days"
ExpiresByType image/jpeg "access plus 14 days"
ExpiresByType image/gif "access plus 14 days"
ExpiresByType image/png "access plus 14 days"
ExpiresByType image/svg+xml "access plus 1 month"
ExpiresByType text/html "access plus 14 days"
ExpiresByType video/ogg "access plus 1 month"
ExpiresByType audio/ogg "access plus 1 month"
ExpiresByType video/mp4 "access plus 1 month"
ExpiresByType video/webm "access plus 1 month"
ExpiresByType application/x-font-woff "access plus 1 month"
ExpiresByType application/vnd.ms-fontobject "access plus 1 month"
ExpiresByType application/xml "access plus 0 seconds"
ExpiresByType application/json "access plus 0 seconds"
ExpiresByType application/rss+xml "access plus 1 hour"
ExpiresByType application/atom+xml "access plus 1 hour"
</IfModule>
Gzip compression on text-based content
<IfModule mod_deflate.c>
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript
</IfModule>
While it is just this I definitely use because it is common benefits. But later if there is more then I will add again.