That's not how site optimization works. Joomla can have any number of extensions installed, which also affect performance. You could have any number of server configurations causing performance problems. You could have any number of database configurations causing performance problems.

Your database is not CB. It's Joomla. We add very few database tables to Joomlas database, which is powered by your server host.

We can not know what fields, plugins, etc.. you plan to create or install so large sites need to usually manually create custom database indexes as needed (shouldn't be needed unless you've something like 500,000+ users). Again, see below for what support provides.

www.joomlapolis.com/help-us-help-you

You've also provided very little as to what your issue even is. What performance problems exactly? Is backend just loading slow? Only in the control panel and CB or also in Joomla backend component views? Does the backend control panel not load at all? Have you tried disabling CBs admin modules in Extensions > Modules? Have you tried disabling the version checking within CB > Configuration > Integrations? Your issue could simply be due to the HTTPS calls for version checking taking too long.