There is no free, reliable, and fully automated Ioncube decoder for PHP 7.2 that can reconstruct original source code with 100% accuracy. Most tools claiming to do so are either scams, malware, or only work on older Ioncube versions (pre-PHP 5.4).
Even after these steps, you will not recover comments, original indentation, or meaningful variable names. For a 10,000-line encoded app, this approach is impractical. ioncube decoder php 72
If you need source code access, contact the software vendor. Many will provide unencoded versions upon proof of license ownership. The Ultimate Guide to Ioncube Decoder for PHP 7