Hello @Ibrahim_Hegazi and welcome.
Check that your server has the minimum recommended specifications to act as a Web Server and run Magento. If you do, then work through this article: Why is Magento 2 so slow? 12 EASY Tips to make Magento 2 faster
I don’t understand the question. Don’t forget, you can’t just reassign an IP or domain name without updating the Base URLs in the Magento configuration. So, if the Public IP is 123.123.123.123 then the Base URL needs to say that too.