What you really need is some kind of Angular/Webpack plugin that add obfuscated code to call out to some 3rd-party escrow/broker service to check if a flag has been raised and if so refuse to load. If you only had access to the final bundled code it might be hard to find what part to rip out (think like the "Preview" or "Sample" slightly opaque text on images. Then you could deliver the final product sans "DRM" after payment.

I think this could be thwarted with a CSP policy? Not really sure.