I checked your website, and it doesn't look related to the server, and it's not related to PHP version. You do have several custom javascripts and css, and there are some errors in console, which look like are breaking the page:
I see you are loading some custom font awesome javascript, as well as several custom CSS stylesheets. X3.29 is using latest jQuery 3.5, and it's not unthinkable that something is not compatible. I couldn't quite identify exactly where the problem lies, but if I was to diagnose, I would first test without any of your custom JS/CSS.
You can test yourself, or if you want me to diagnose, please provide login to your panel by private message. In either case, I would recommend you to make a backup of your /config/config.user.json file before editing settings.