You have asked a very vague question. First we need to know the OS version, Apache version, Apache modules installed, Mysql version, PHP version, if the server is SSD, Apache configuration file, PHP ini, and network speed.
As you can see there are a lot of factors that come into play when measuring server elasticity.
Memory (ram) plays an important role in how many processes you can run at a time on your server, this depends on the applications you are hosting.
If you are facing high traffic issues, you may want to consider moving over to nginx.
Also ensure your PHP version is 7+.
Also note, unless your running an extremely active service having 1000 simultaneous connections is pretty rare.
I host 400 highly active businesses across the US on a single VPN and i have still never gotten 1000 simultaneous connections.
please note that, i offer direct support that is in no way associated with GoDaddy's regular support channels; but, for immediate technical support you can contact me at: https://join.skype.com/t3cxhmNCspqu