I think your energies are better for setting milestones in your project that are tied to payments. This is ideally done in steps, so that neither side feels at a disadvantage regarding the amount of work performed / the amount of money paid.
Obfuscation is easily removed and decoded, as a rule.
Remote verification of the security license opens a hole for the security of the application and can also be easily defeated.
Entering a code that "self destructs" if any action or code is not deleted is also not a big practice.
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