Professional developers generally recommend focusing on high-quality code and reasonable security rather than trying to build a 100% "hack-proof" app.
It is understandable to look for ways to save on development costs, but using a "crack" for Xojo (or any development tool) is generally a bad move for several practical reasons that go beyond just the legal risks.
While there are websites that claim to offer "cracks" or "license key generators" for Xojo, these files are generally highly dangerous
Cracked software often suffers from frequent crashes or missing features, which can ruin hours of coding work.
Many "crack" files are bundled with malware, keyloggers, or ransomware that can compromise your entire development machine.