What determines the loading speed of a site on Joomla?

Question

Joomla

Hello! Subject.
It is planned to make a service with user registration and the ability to post ads (something like Avito, for only one service) and the visit will be, well, a maximum of 700 people per day. But even with this, a poorly configured Joomla can freeze, this would not be desirable.
I heard that when too many queries come into the database, it can freeze. For what else?
Cloud hosting.
Or maybe something else to take for these purposes?