Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
If you are still using CentOS 7.9, it's time to convert to Alma 8 with the free centos2alma tool by Plesk or Plesk Migrator. Please let us know your experiences or concerns in this thread: CentOS2Alma discussion
I have another suggestion for you
You can use free existing CDNs like cloudflare and you can add any record you need. I think your problem is not related to the server.
Also, if you have not set your rDNS record, you can ask your provider's support