Many free tools exist that claim to edit Tyrano saves, but they are often "Lite" versions. Here is what a version typically offers that basic versions lack:
Galactic647/Tyrano-Save-Reader: Tools to convert ... - GitHub
Editing your local save file is not illegal in most jurisdictions. You own the save data on your hard drive. However, modifying online leaderboards or Steam Achievements (triggering them without playing) violates Steam's subscriber agreement.
: Use the official TyranoStudio for debugging and checking data during active development.