There is a support site for BridgeDD: https://bridgedd.com/support
There have been no recent questions from anyone about an issue with Xcache. (XCache has nothing to do with security.) Had you asked, I would have told you about a line that could be added to the BridgeDD configuration file that bypasses the check for XCache. It is not documented because bypassing the check for XCache can be dangerous if one does not understand their XCache configuration. You could have also done a site search and found the answer yourself.
I would like to know the name of your hosting company, because they have flat-out lied to you about both BridgeDD and the need for XCache. I’ll leave the XCache issue alone since it’s not particularly relevant to this discussion.
BridgeDD only requires that PHP runs as the same user who owns the WordPress and phpBB files. This is the modern way to configure PHP, in most cases through the use of PHP-FPM. I strongly suspect your hosting company uses ancient PHP configurations because they’re easier to install and support. (They are also much less secure, but I’ll leave that issue alone, too.)
In any case, I’m sorry you were unhappy with BridgeDD. Perhaps when you move to a better hosting company that supports modern PHP configurations and doesn’t lie to its customers, you can revisit the product.
