Migrate to PHP 8.0 or 8.1. For encoded scripts, request updated versions from the vendor. If the vendor is gone, consider rewriting the functionality or switching to open-source alternatives.
"Site error: the ionCube loader needs to be installed. The encoded file requires the ionCube PHP Loader for PHP 7.2 to be installed." ioncube decoder php 7.2
Technically, there is no official "ionCube Decoder." ionCube is designed to be a one-way street. Migrate to PHP 8