The main advantage premium hosting has for you right now is that premium hosting has a PHP version selector, which lets you downgrade your account to PHP 7.4. If upgrading to PHP 8.2 is not feasible right now, for example because the software you’re using hasn’t been updated to be compatible with PHP 8.2 yet, that may help you get your website online.
Premium hosting does include ticket support. However, please be aware that premium hosting is not managed hosting, you’re still responsible for maintaining your own website.
I noticed I forgot to link to this KB article:
This guide helps to get more useful errors. I enabled it on your site, and saw this error:
Fatal error: Array and string offset access syntax with curly braces is no longer supported
That very clearly indicates that the issue is caused by your website containing code that’s not supported by this PHP version.
While looking to see what the status is at PivotX regarding support for PHP 8, it looks… disappointing.
According to both Wikipedia and Softaculous, the last release of PivotX was from 2015. The official website pivotx.net appears to be down. However, it does seem that someone (who I’m not sure is the original creator) is continuing the development of PivotX on GitHub, with a prerelease version that support PHP 8.2: Release 3.0.0 RC 3 · pivotx/PivotX · GitHub
For now, you could either choose to upgrade to premium hosting (so you can run an older PHP version where your site can still run on), or perhaps try updating your website using the prerelease version of PivotX 3 from GitHub.
Also, I merged your topics.