How can I unblock my own personal website from being opened on my iPhone?

Please be more specific on describing the issue that you're facing, but according to what you've said, these are the things that you should know

1. Check if screen time content restriction is enabled
2. Change your DNS to more popular ones, which gets updated more frequently (if you're using WiFi)
3. Use a VPN, the server that you're hosting your website on may be restricted by your ISP
4. Restarting your phone, this should clear the DNS cache
5. If you're using an older device, some website may not be able to load properly
6. Check if Javascript is enabled

So you mentioned "unblock" which means you have somehow blocked it yourself ?

What happens when you try? This is to vague to be able to address.